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- Herausgeber: John Wiley & Sons
- Kategorie: Fachliteratur
- Serie: Bioprocessing in Food Science
- Sprache: Englisch
Nutraceuticals from Fruit and Vegetable Waste
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Veröffentlichungsjahr: 2024
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Table of Contents
Cover
Table of Contents
Series Page
Title Page
Copyright Page
Preface
1 Valorisation of Fruit and Vegetable Waste
1.1 Introduction
1.2 Valorisation of By-Products from Fruit and Vegetable Processing Industry
1.3 Conclusion
References
2 Nutraceuticals from Guava Waste
Abbrevations
2.1 Introduction
2.2 Guava Waste Types and Composition
2.3 Bioactive Potential of Guava Waste
2.4 Application of Guava Waste
2.5 Conclusion
References
3 Nutraceuticals from
Emblica officinalis
Waste
3.1 Introduction
3.2 Composition of Amla Waste
3.3 Utilization of Amla Waste
3.4 Pharmaceutical Potential of Amla Waste
3.5 Other Amla Waste
3.6 Conclusion
References
4 Nutraceuticals from Apple Waste
4.1 Introduction
4.2 Nutritional Profile and Physicochemical Composition
4.3 Bio-Actives and Functional Ingredients from Apple Pomace
4.4 Extraction of Bioactives from Apple Pomace
4.5 Use of Apple Pomace for Various Applications
4.6 Future Prospects and Conclusion
References
5 Avocado
5.1 Introduction
5.2 Nutritional Composition of Fruit Waste
5.3 Phytochemical Composition of Avocado Waste
5.4 Pharmaceutical Potential of Fruit Waste
5.5 Other Methods of Utilization
5.6 Conclusion
References
Websites
6 Banana Waste as a Nutraceuticals Product
6.1 Introduction
6.2 Chemical Composition
6.3 Medicinal Properties
6.4 Utilization of Banana Waste
6.5 Development of By-Products from Banana Waste
6.6 Summary
Abbreviations
References
7 Burmese Grape
7.1 Introduction
7.2 Burmese Grape Fruit and Fruit Waste
7.3 Nutraceuticals and Functional Activities of Burmese Grape Waste
7.4 Burmese Grape Tree Parts
7.5 Conclusion
List of Abbreviations
References
8 Citrus
8.1 Introduction
8.2 Phytochemicals in Citrus Waste
8.3 Principal Non-Conventional Technologies to Extract High Biological Value Compounds from Citrus Waste
8.4 Citrus Waste and Its Utilization
8.5 Conclusion
References
9 Dates
9.1 Introduction
9.2 Date Seeds
9.3 Integrating Dates with Food for Developing Value-Added Recipes
9.4 Nutritional Benefits
9.5 Antioxidants and Phytochemicals in Dates
9.6 Health Benefits
9.7 Conclusion
References
10 Ginger (Zingiber officinale)
10.1 Introduction
10.2 Ginger Varieties and Its Features
10.3 Nutritional and Phytochemical Components of Ginger
10.4 Processing of Ginger
10.5 By-Products Generated from Ginger Processing
10.6 Nutraceutical Potential and Utilization of Ginger By-Products
10.7 Future Prospects
References
11 Jackfruit
11.1 Introduction
11.2 Types of Jackfruit Waste and By-Products
11.3 Nutraceuticals and Functional Activities of Jackfruit Waste and By-Products
11.4 Parts of Jackfruit Tree
11.5 Conclusion
List of Abbreviations
References
12 Development of Nutraceuticals from the Waste of Loquat
12.1 Introduction
12.2 Importance of Waste Material of Fruits
12.3 The Worldwide Growth Pattern of Loquat
12.4 Physiology and Biochemistry of Loquat
12.5 Use of Loquat Tree and Its Parts
12.6 Nutraceutical Properties
Conclusion
References
13 Mango
13.1 Introduction
13.2 Mango Peel
13.3 Nutritional Composition
13.4 Phytochemical Composition
13.5 Utilization of Mango Peel
13.6 Mango Kernel
13.7 Nutritional Composition of Mango Kernel
13.8 Phytochemical Composition of Mango Kernel
13.9 Utilization of Mango Kernel
13.10 Other By-Products of Mango Waste
References
14 Melon
14.1 Introduction
14.2 History, Origin and Domestication
14.3 Diversity and Botanical Groups of Melon
14.4 Consumer Preference for Melon
14.5 Nutritional Importance, Health Benefits and Culinary Uses of Melon
14.6 Fruits and Vegetables Wastage
14.7 Melon Waste: Seed and Peel
14.8 Melon Seed
14.9 Melon Rind/Peel
14.10 Nutraceutical Potential and Health Benefits from Melon Waste
14.11 Applications of Melon Waste
14.12 Conclusion
References
15 Okra (
Abelmoschus esculentus
)
15.1 Introduction
15.2 Bioactive Constituents
15.3 Nutritional Constituents
15.4 Nutraceutical Applications
15.5 Pharmacological Potential Applications
15.6 Mechanisms of Action of Bioactive Components
15.7 Abelmoschus Esculentus in Waste Treatment
15.8 Conclusion
Abbreviations
Conflict of Interest
Acknowledgement
References
16 Papaya Waste as a Nutraceuticals Product
16.1 Introduction
16.2 Nutritional Composition
16.3 Nutraceutical Application
16.4 Conclusion
Abbreviations
References
17 Peach (
Prunus persica
(L.)
Batsch
)
17.1 Introduction
17.2 Nutritional Composition of Peach Wastes
17.3 Phytochemical Composition of Peach Wastes
17.4 Pharmaceutical Potential of Peach Wastes
17.5 Industrial Utilization of Peach Wastes
17.6 Conclusion
References
18 Pumpkin (
Cucurbita
)
18.1 Introduction
18.2 World Production Scenario of Pumpkin
18.3 Pumpkin Seed
18.4 Pumpkin Peel
18.5 Conclusion
Conflict of Interest
References
Index
Also of Interest
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Bioactive compounds reported in fruit and vegetable waste.
Chapter 2
Table 2.1 Proximate analysis of different types of guava waste.
Table 2.2 Vitamins and minerals composition of guava waste.
Table 2.3 Bioactive compounds profile of guava waste.
Chapter 3
Table 3.1 Common name of Amla in different languages [1].
Table 3.2 Nutritional and phytochemical composition of amla (
Emblica officinal
...
Chapter 4
Table 4.1 Nutritional composition of apple pomace (wet weight basis).
Table 4.2 Nutritional composition of apple pomace (dry weight basis).
Chapter 5
Table 5.1 Vernacular names and Nomenclature profile of avocado [129, 130].
Table 5.2 Commonly cultivated avocado varieties worldwide (109).
Table 5.3 Comparison table depicting the nutritional composition of avocado fr...
Table 5.4 Bioactive constituents data of avocado waste.
Table 5.5 Phytochemical composition of avocado waste.
Chapter 6
Table 6.1 Antimicrobial contents found in different banana parts.
Chapter 7
Table 7.1 Fatty acid profile of burmese grape seed oil [31,33].
Table 7.2 Different types of polysaccharides found in burmese grape seed powde...
Table 7.3 Total phenolic and flavonoid contents, and antioxidant activities of...
Table 7.4 FRAP activity of standard and methanolic extracts of burmese grape f...
Table 7.5 Depressant effects of the burmese grape seed methanol extract on hol...
Table 7.6 Proximate composition of burmese grape peel [17].
Table 7.7 Different types of polysaccharides found in burmese grape peel powde...
Table 7.8 The effect of burmese grape leaves methanolic extract on lipid profi...
Chapter 9
Table 9.1 Nutrient value of date and nut dark chocolate candy [9].
Table 9.2 Macronutrient content for date [24].
Table 9.3 Nutritional content for date seeds [4].
Table 9.4 Nutritive value of dry dates [9].
Chapter 10
Table 10.1 Ginger variety diversity in India [9].
Table 10.2 Characteristics with fiber, olioresin and ginger oil in some common...
Table 10.3 Chemical compounds identified from ginger rhizomes peel.
Chapter 11
Table 11.1 Jackfruit seed composition (per 100 grams edible portion) [2].
Table 11.2 Total phenolic and total flavonoid content, antioxidant activities ...
Table 11.3 Organic acid content in jackfruit seed kernel and seed coating memb...
Table 11.4 Proximate composition of dried jackfruit peel powder [87].
Table 11.5 Elemental/mineral contents of jackfruit peel [91].
Table 11.6 The average composition of phenolic, flavonoid and tannin content o...
Chapter 12
Table 12.1 Clinical importance of the waste of some common fruits.
Table 12.2 Loquat prevalent names in different native regions.
Table 12.3 Products or nutraceuticals which are prepared worldwide using the w...
Chapter 13
Table 13.1 Physicochemical composition of mango peel.
Table 13.2 Vitamin and mineral elemental composition of mango peel.
Table 13.3 Phenolic compounds present in mango peel on the dry basis.
Table 13.4 Chemical characteristics of mango seed.
Table 13.5 Mineral elemental composition of mango kernel.
Table 13.6 Compounds found in mango kernel.
Chapter 14
Table 14.1 Consumer preferences of different types of melon [41].
Table 14.2 Nutritional facts of melon.
Table 14.3 Proximate composition of melon by products (seed and peel) obtained...
Table 14.4 Nutritional profile of melon seed.
Table 14.5 Oil content of melon seeds obtained from different varieties.
Table 14.6 Fatty acids profile (%) of melon seed obtained from different varie...
Table 14.7 Triglyceride profile (%) of melon seed obtained from different vari...
Table 14.8 Total phenolics and flavonoid content in melon seed obtained from d...
Table 14.9 Tocopherol and tocotrienol composition of melon seed oils obtained ...
Table 14.10 Nutritional profile of melon peel.
Table 14.11 Total phenol and flavonoid content in melon peel obtained from dif...
Table 14.12 Quantification of total phenolic compounds of melon peel extracts ...
Table 14.13 Antioxidant properties of melon pulp, peel and seed extracts obtai...
Chapter 15
Table 15.1 Scientific classification of
Abelmoschus esculentus.
Table 15.2 Nutritional composition of raw okra and okra seeds.
Table 15.3
Abelmoschus esculentus
(okra) utilisation.
Table 15.4 Therapeutic applications of
Abelmoschus esculentus.
Table 15.5 Composition of extracted polysaccharides in okra.
Chapter 16
Table 16.1 Medicinal properties of papaya.
Chapter 17
Table 17.1 Composition of different layers of peach [46, 47].
Table 17.2 Taxonomic classification of
Prunus Persica
[28].
Table 17.3 Indian peach production [77].
Table 17.4 Nutritional composition of peach pulp, peel, seed (whole) and kerne...
Table 17.5 Nutritional composition of peach pomace.
Table 17.6 Bioactive components of peach pulp, peel and seed (kernel).
Table 17.7 Phytochemical composition of peach pulp, peel and seed (kernel).
Table 17.8 Fortified food products of peach wastes.
Chapter 18
Table 18.1 World production scenario of pumpkin (Tonnes).
Table 18.2 Proximate composition of pumpkin by-products.
Table 18.3 Mineral composition of pumpkin by-products (mg/100g dry weight).
Table 18.4 Bioactive compounds in pumpkin by-products.
Table 18.5 Fatty acid composition of pumpkin seeds (% fatty acid).
List of Illustrations
Chapter 1
Figure 1.1 Waste generated from various fruits and vegetables (Modified from D...
Figure 1.2 Valorisation of fruit and vegetable waste.
Figure 1.3 Techniques for the extraction of bioactive compounds from fruit and...
Chapter 2
Figure 2.1 Guava tree and its by-products.
Chapter 3
Figure 3.1 Statewise share (percentage) of
Emblica officinalis
production in I...
Figure 3.2 (a) Different parts of amla fruit. (b) Composition of amla whole fr...
Figure 3.3 Structure of bioactive compounds present in amla seed.
Chapter 4
Figure 4.1 Various constituents of apple pomace or bio-waste.
Figure 4.2 Schematic representation of bio-active components from apple pomace...
Chapter 5
Figure 5.1 Stages of ripening of avocado fruit [128].
Figure 5.2 Production scenario of avocado. (a) Worldwide data representing gro...
Figure 5.3 Geographic representation of global avocado market size [134].
Figure 5.4 Avocado whole fruit and its waste products (peel, seed, pulp).
Figure 5.5 Recent potential utilization of avocado waste [127].
Chapter 6
Figure 6.1 Waste generated from banana in various processes.
Figure 6.2 Process of developing the nutraceuticals with banana by-products.
Figure 6.3 Valorisation of banana waste.
Chapter 7
Figure 7.1 (a) Burmese grape is growing on the tree; (b) Edible pulp after rem...
Figure 7.2 Anti-inflammatory effects of the methanol extract (200 mg/kg, p.o.)...
Figure 7.3 Effect of Burmese grape seed extract and rosuvastatin on lipid prof...
Chapter 8
Figure 8.1 Basic principle of ultrasound-assisted extraction.
Figure 8.2 Basic principle of microwave-assisted extraction.
Figure 8.3 Flow diagram of supercritical fluid extraction.
Figure 8.4 Flow diagram of pressurized water extraction.
Figure 8.5 Flow diagram of pulsed electric field.
Figure 8.6 Flow diagram of high hydrostatic pressures.
Figure 8.7 Mechanism of action of enzyme-assisted extraction.
Figure 8.8 Citrus, its parts, utilization of by products and citrus fruits was...
Chapter 9
Figure 9.1 Varieties of dates [12].
Figure 9.2 Growth cycle of dates [12].
Figure 9.3 Process of making date-based chocolate.
Figure 9.4 Pie chart for antioxidant capacity of various varieties of dates (2...
Chapter 10
Figure 10.1 Indian ginger rhizome germplasm variability features reported by K...
Figure 10.2 Processed products of ginger rhizomes.
Figure 10.3 By-products of ginger from farm to plate.
Chapter 11
Figure 11.1 (a) Different sizes of jackfruit hanging on the tree; (b) differen...
Figure 11.2 DPPH scavenging ability of different parts of jackfruit [61].
Chapter 12
Figure 12.1 Presentation of clinical importance of Loquat.
Figure 12.2 Pictorial categorisation of bioactive compounds present in Loquat.
Chapter 13
Figure 13.1 Various steps of mango processing that generated mango waste.
Chapter 14
Figure 14.1 Chemical structure of tocochromanols.
Figure 14.2 Structure of phenolic compounds present in melon peel [108, 134].
Figure 14.3 Chemical structure of major carotenoids having provitamin A activi...
Chapter 16
Figure 16.1 By-products of papaya.
Figure 16.2 Seed oil extraction procedure in papaya.
Figure 16.3 Steps involved in preparation of papaya peel silver nitrate nano p...
Figure 16.4 Procedure of developing bast fiber in papaya.
Figure 16.5 Preparing of papaya bast fibre.
Chapter 17
Figure 17.1 Peach fruit, seed and kernel.
Figure 17.2 Global production of peach 2016-2020 [74, 75].
Figure 17.3 Top peach-producing countries - 2020 [74, 75].
Guide
Cover Page
Table of Contents
Series Page
Title Page
Copyright Page
Preface
Begin Reading
Index
Also of Interest
WILEY END USER LICENSE AGREEMENT
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Scrivener Publishing100 Cummings Center, Suite 541JBeverly, MA 01915-6106
Bioprocessing in Food Science
Series Editor: Anil Panghal, PhD
Scope: Bioprocessing in Food Science will comprise a series of volumes covering the entirety of food science, unit operations in food processing, nutrition, food chemistry, microbiology, biotechnology, physics and engineering during harvesting, processing, packaging, food safety, and storage and supply chain of food. The main objectives of this series are to disseminate knowledge pertaining to recent technologies developed in the field of food science and food process engineering to students, researchers and industry people. This will enable them to make crucial decisions regarding adoption, implementation, economics and constraints of the different technologies. Bioprocessing has revolutionised the food industry by allowing for more efficient and sustainable production methods. This comprehensive series will be focused on microbial fermentation, enzyme technology, genetic engineering, microbial transformations, and bioreactor design. As we continue to face challenges such as population growth and climate change, bioprocessing will play an increasingly important role in ensuring a sustainable food supply for future generations.
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Publishers at ScrivenerMartin Scrivener ([email protected])Phillip Carmical ([email protected])
Nutraceuticals from Fruit and Vegetable Waste
Edited by
Vidisha Tomer
Navnidhi Chhikara
Ashwani Kumar
and
Anil Panghal
This edition first published 2024 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA© 2024 Scrivener Publishing LLCFor more information about Scrivener publications please visit www.scrivenerpublishing.com.
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Library of Congress Cataloging-in-Publication Data
ISBN 978-1-119-80350-8
Cover image: Food Waste: Stockcube | Dreamstime.com, Nutraceuticals: Marina Cavusoglu | Dreamstime.comTablet press machine: Liliia Kanunnikova | Dreamstime.comCover design by Kris Hackerott
Preface
Fruits and vegetables are inherent components of healthy dietaries. However, in the span of production to consumption, these generate huge quantities of waste. As per estimates by various agencies, approximately 20 – 40 percent of the total production of fruits and vegetables is wasted. Significant losses and waste in the fresh fruit and processing industries are becoming a serious nutritional, economical, and environmental concern. The inherent nature of perishability is the major factor attributed for this loss. However, they manner in which most fruits and vegetables are consumed itself generates waste, wherein the edible part is sometimes even less than half of the total weight of the fruit. Enhanced fruit and vegetable production has made it as one of the highest wastes generating sector (approximately 42 percent). During processing and consumption, by products in the form of seeds, peels, pomace, stones, rind, pods etc. are generated. These parts abode nutrients in abundance, in some cases more than the fruit itself. There is an urgent need to recover value from this waste rather than to commit it to handful of other disposal methods. Long-term disposal of these remnants not only facilitates a breeding ground to microbes, insects, pests and mice but also incurs a huge cost to the environment by contributing significantly to greenhouse emissions. Valorisation of waste can be a key not only for better utilization but also for reducing environmental burden. The by-products obtained from the industry can be transformed into various useful end products like ethanol, enzymes, nutraceuticals etc.
One step for valorisation of fruit and vegetable waste can be through harnessing its nutraceutical potential. It has been identified through various studies that waste components are rich in potentially valuable bioactive compounds, such as carotenoids, polyphenols, dietary fibers, vitamins, enzymes, and oils, among others. These phytochemicals can be utilized in different industries including the food industry, for the development of functional or enriched foods, the health industry for medicines and pharmaceuticals, and the textile industry, among others. However, these generally have not received much attention as antioxidant and nutrient source majorly due to lack of popularity and limited commercial applications.
This book is a comprehensive compilation which explores and conveys the key concepts for understanding the nutraceutical potential of fruit and vegetable waste for ensuring better utilization of these components in nutrition and health. It deals with the composition, methods of utilization and potential human health benefits of fruit waste.
The collection and compilation of fruit waste composition, utilization and health benefits will prove to be an important addition to the body of knowledge. We believe that this book will be interesting and useful to all concerned about the ever-growing volume of waste generated and for those who want to harness the hidden potential of the waste.
Vidisha TomerNavnidhi ChhikaraAshwani KumarAnil Panghal
1Valorisation of Fruit and Vegetable Waste
Vidisha Tomer1*, Ashwani Kumar2, Navnidhi Chhikara3 and Anil Panghal4
1VIT School of Agricultural Innovations and Advanced Learning, Vellore Institute of Technology, Vellore, Tamil Nadu, India
2Rani Lakshmibai Central Agricultural University, Jhansi, Uttar Pradesh, India
3Department of Food Technology, Guru Jambheshwar University of Science and Technology, Hisar, Haryana, India
4Department of Processing and Food Engineering, AICRP-PHET, Chaudhary Charan Singh Haryana Agricultural University, Hisar, India
Abstract
The ever-increasing global population indicates that food demand will rise for at least another forty years, which will exert immense pressure on our limited natural resources. Hence, wise use of available resources, maximum utilization of available food and minimization of food waste is crucial. Due to their perishable nature, the highest wastage of food occurs in the fruit and vegetable sector, which is approximated to about 30-44%. The fruits contain various unused parts like peel, seed and pomace which sometimes may account for approximately half of the fruit, e.g., pineapple, mango. These components are rich in sugars, pectin, fats, cellulose, hemicelluloses, minerals, and vitamins, which in some cases are richer than the fruit itself. This can be bio-converted into useful products such as acids, alcohols (bioethanol), enzymes, fuels, and value-added products. The seeds and pits can also be used for the extraction of edible grade oils. This chapter introduces and summarises the methods by which fruit and vegetables have been valorised into useful products.
Keywords: Pigments, essential oil, nutraceuticals, bioactive compounds, phytochemicals
1.1 Introduction
With increasing population, the quantity of food required is also increasing, which exerts immense pressure on our natural production mechanisms (Panghal et al., 2021). In addition, it also becomes a source of generation of additional food waste. Trends indicate food demand will rise for at least another forty years. Hence, wise use of available resources, maximum utilization of available food and minimization of food waste is crucial. As per the Food and Agriculture Organization, food loss is “a decrease in quality and quantity of food” (Diaconeasa et al., 2023). Food waste can occur at any step of the supply chain. In the fruit and vegetable processing industries the major waste is generated through the left over and inedible parts of fruits and vegetables. This adds burden on the waste management systems, exacerbates food insecurity and is the biggest source of greenhouse emission. According to the Food Waste Index Report 2021, the food service industry produces 931 million tonnes of waste each year and a large chunk of this (570 million tonnes) is generated at the household level (United Nations Environment Programme, 2021). One-third of the total food produced is wasted and this is estimated to be worth one trillion USD. As per the reports of United Nations Environment Program Publications, the highest wastage of food occurs in the fruit and vegetable sector, which is approximated to about 30-44% (Barrera and Hertel, 2021; Cronjé et al., 2018).
India is the second-largest producer of fruits and vegetables in the world and the food processing sector has been growing at an Average Annual Growth Rate (AAGR) of 10%. However, the postharvest losses are still high and almost 30-40% of fruits and vegetables in the country go to waste (National Herald, 2021). According to the Annual Report 2020-21, published by Ministry of Food Industries, the postharvest losses of major agricultural produce at national level was 92,651 crore Indian Rupees calculated using production data of 2012-13 at 2014 whole sale prices (MOFPI, 2021). The major waste generated from fruit and vegetables is in the form of peels, seeds and pits. For example, apples contain 10.9% as seed, pulp and peel as by-products. Minimal processing treatments like dicing produces only 53% of the fruit as final product and the rest is waste in the form of peel, seed and unusable pulp. Similarly, pineapple processing produces approximately 50% of waste in the form of peel, core, top and pulp (14, 9, 15, 15% respectively). In mango as well, only 58% of the fruit is utilised. Figure 1.1 summarises the waste generated from different fruits and vegetables. The fruit and vegetable juice industry produces around 5 MMT of solid waste and the canning and frozen food industry is responsible for almost an equal amount of waste generation (Sagar et al., 2018). Waste is a big environmental burden.
Currently, fruit and vegetable waste is managed either by incineration or by landfill, owing to its biodegradable nature. The process of incineration results in gradual production and ejection of various primary and secondary compounds which may act as pollutants like gases, acids, etc. Inadequate landfill management leads to release of gases like methane, carbon dioxide, etc., which may impose not just environmental damage but also health risks (Sindhu et al., 2019; Rifna et al., 2021). In addition, this so-called waste is rich in sugars, pectin, fats, cellulose, hemicelluloses, minerals, and vitamins. This can be bio-converted into useful products such as acids, alcohols (bioethanol), enzymes, fuels, and value-added products (Verma and Kumar, 2020). The seeds and pits can also be used for the extraction of edible grade oils. This chapter introduces and summarises the methods by which fruit and vegetables have been valorised to something useful.
Figure 1.1 Waste generated from various fruits and vegetables (Modified from Dalal et al., 2020).
1.2 Valorisation of By-Products from Fruit and Vegetable Processing Industry
Valorisation of waste can be a key not only for better utilization but also for reducing the environmental burden. The by-products obtained from the industry can be transformed into various useful end products like ethanol, enzymes, nutraceuticals, etc. (Figure 1.2). This section deals with the products that fruit and vegetable waste and by-products can be transformed into.
1.2.1 Oil
The seeds of the fruits, especially the stone fruits like mango (Mangifera indica), peach, apricot, and avocado, etc., can be used for the extraction of oil. The yield of the oil varies with the particle size, volume of solvent, temperature and time of extraction. Yadav et al. (2017) reported that the highest yield (15.20%) of oil from the kernels of mango stone (25 g sample extracted with 250 ml n-hexane) can be obtained at a particle size of 1 mm and extraction time of 90 minutes. Karunannithi et al. (2015) optimized soxhlet solvent extraction process for the extraction of mango seed kernel oil using n-hexane. It was found in the study that minimum solvent requirement and time for the extraction of 20 g of mango seed kernel at 40-70 °C was 200 ml, and 3 hours, respectively. The extraction rate of the oil under these conditions was 12%. The composition of mango seed kernel oil is very similar to cocoa butter except the iodine value is higher in mango seed kernel oil than in cocoa butter. The specific gravity of oil is 0.912, refractive index is 1.46, saponification value is 187.7, iodine value is 49.4 and acid value is 1.93 (Moharram and Moustafa, 1982). The stearic acid, oleic acid, linoleic acid and palmitic acid content of mango seed kernel oil is 58.08%, 17.99%, 2.86%, and 1.33%, respectively. The oil is edible and has lower free fatty acids, carotenoid content and peroxidase value and is generally used without any processing. The melting point of oil is 32-36°C and is solid at room temperature. Mango kernel oil is also high in unsaponifiable matter and is extensively used in the cosmetic industry (Yadav et al., 2017). Wu et al. (2011) optimized the extraction process of peach kernel oil using different solvents, i.e., petroleum ether, ethyl ether, chloroform and hexane. The oil extracted with hexane was found to have the highest overall acceptability. The oil is edible and has a high level of unsaturated fatty acids (91.27%). The major fatty acids in peach kernel oil are oleic acid (61.87%), and linoleic acid (29.07%). The acid, peroxide, iodine and saponification values of oil were 0.895 mg KOH/g, 0.916 mg/g, 36.328 mg/g and 101.836 mg KOH/g, respectively. It was also found to have high phenolic compounds (4.1593 mg GAE/g).
Figure 1.2 Valorisation of fruit and vegetable waste.
Savic et al. (2020) optimized the soxhlet extraction process for the extraction of plum seed kernel oil using various solvents, i.e., n-hexane, n-heptane, ethyl acetate, acetone or a mixture of chloroform and ethanol (2:1 v/v). Among the various solvents, the highest oil yield was obtained for n-heptane (30.5%) and n-hexane (30%), while the lowest yield was obtained for ethyl acetate (23.5%). The obtained oil had a density varying from 0.50-1.10 g/mL (varied according to the solvent used), refractive index of 1.47, viscosity of 135.40-183.20 mPas, pH of 3.43-4.63, acid value of 1.41-2.81 mg KOH/g, saponification value of 180-198 mg KOH/g and peroxide value of 1.82-3.75. Plum kernel oil is also rich in unsaturated fatty acids (oleic acid, 52-66%, linoleic acid, 28-35%, α-linoleic acid, 0.2%) and the content of saturated fatty acids is very low (5.8-11.3%). This oil is also rich in phenolics and possesses good antioxidant properties. All these attributes make it a good fit for food applications and is also an excellent base for the development of cosmetic products and mature skin. Apricot seed yields about 22-38% kernels (Kate et al., 2014). The oil recovery can also be enhanced by the use of enzymes. Bisht et al. (2015) conducted a study examining the effect of enzymes (pectinase, cellulose, pectinase + cellulose) on the oil extraction efficiency from wild apricot. The enzymes were mixed with kernel powder and were kept at 50±2 °C for 2 hours before oil extraction using expeller. The enzymatic treatment enhanced the oil recovery by 9-14.22%. Maximum oil recovery was obtained at 0.3-0.4% enzyme concentration for both the enzymes individually, as well as in combination. The highest oil yield (47.33%) was obtained for the blend of enzymes used at a concentration of 0.3%. The oil recovery was increased by 14.22% by the enzymatic treatment in comparison to the control that had an oil yield of 33.11%. These were a few examples depicting the scope of application of kernel oils in various industries based on the physical and chemical properties they exhibit.
1.2.2 Essential Oils
Essential oils are concentrated hydrophobic liquids that are a mixture of many volatile aromatic compounds such as isoprenoids, monoterpenes, and sesquiterpenes and are responsible for the fragrance of many aromatic plants. Many other names like aromatic oils, fragrant oils, steam volatile oils and etheral oils are also prevalent for these (Fakayode and Abobi, 2018; Raseem et al., 2016). A number of methods like cold processing, reflux, mechanical stirring, ultrasound-assisted extraction, microwave-assisted extraction and supercritical fluid extraction can be used for their extraction using both organic and green solvents. The organic solvents mostly used are ethanol, methanol, hexane, toluene, and petroleum ether, etc. The green solvents used are water, steam, supercritical CO2 and ionic solvents, etc. Fakayode and Abobi (2018) optimized the effect of extraction temperatures (80-100°C) and extraction time (120-240 minutes) on the yield of essential oil using 2×5 factorial central composite rotatable design (CCRD) of response surface methodology. For the extraction of oil, the orange peels were pureed in a blender, dried and 5 g of dried puree was extracted in a Soxhlet extractor using n-hexane as solvent. The software generated 13 treatments and the yield of essential oils under these conditions varied from 0.57-3.24%. It was suggested that an essential oil yield of 3.38% can be obtained at the extraction temperature of 95.23°C and extraction time of 23.30 minutes. Ullah et al. (2017) studied the organic solvent (toluene, pentane, and hexane) and ionic liquids [1-butyl-3-methylidazolum bis (trifluoromethyl sulfonyl) [BMIM]NTf2, 1-butyl-3-methylimidazolium chloride [BMIM] Cl, 1-hexyl-3-methylimidazolium acetate [HMIM] Ac, 1-allyl-3-methylimidazolium acetate [AMIM] Ac, 1-butyl-3-methylimidazolium acetate [BMIM] Ac] extraction of essential oil from polygonum minus using four different extraction methods (microwave and ultrasound-assisted extraction, mechanical stirring and reflux extraction) and compared their results. In this study, the plant material was collected, washed thrice with distilled water, dried for 12 days at 45°C in an oven, ground to powder (60-80 mesh size) and extracted. For microwave-assisted extraction, the plant material was mixed with different organic and ionic solvents and the extraction was carried out at 400 W at different solid to liquid ratios at 60°C for 30, 40, 50, and 60 minutes with continuous stirring, with and without Clevenger apparatus in case of organic solvents and 60°C (except BMIM (Cl) where extraction was carried out at 80°C) for 15-25 minutes with Clevenger and 5, 6, 7, and 8 minutes in case of without Clevenger with ionic liquids. The ultrasound-assisted extraction was performed at 60°C [80°C for BMIM (Cl)] at amplitude of 70W for 15-30 minutes in the extraction using all the solvents. For mechanical extraction, the plant material was mixed with 40 ml of solvent and stirred for 60, 80, and 100 minutes at room temperature (25°C) using Ika RW 20 Model. In reflux extraction, the plant material was mixed with 40 ml of solvent in the reaction flask and heated at 60°C [80°C for BMIM (Cl)] for 60-90 minutes. The highest extraction efficiency of essential oil (9.61%) was obtained with the use of Clevenger apparatus in combination with the ionic liquids-based microwave-based extraction techniques using [AMIM] Ac ionic liquids. These oils are widely used in perfumeries, incenses, aromatherapies, cosmetics, medicines and as food additives. They also exhibit antimicrobial properties (Fakayode and Abobi, 2018; Raseem et al., 2016).
1.2.3 Pectin
Pectin is a polymer of α-1,4 linked D-galacturonic acid that is present in the middle lamella of the higher plants. Orange peel and apple pomace contain 20-30% and 10-15% pectin, respectively, and most of the commercial pectin is extracted from these sources. The quality and purity of pectin vary depending upon the content of anhydrogalacturonic acid, degree of esterification and ash content. Pectin having high molecular weight, galacturonic acid content and low ash content is said to be of superior quality. A number of extraction methods such as solvent extraction method, microwave- and ultrasound-assisted extraction, subcritical water extractions and enzyme-assisted extractions can be employed for pectin extraction. The method of pectin extraction also affects the structure and functional properties of pectin. Based on the methylation of carboxylic acid groups the pectin can be further divided into high methoxy (HM) and low methoxy (LM) pectins. HM pectin has a degree of esterification in the range of 43-67%, while less than 40% is found in LM. Conventional methods of pectin extraction involves use of mineral or organic acids for facilitating its release from the matrix. In comparison to lactic acid, nitric acid, hydrochloric acid, sulphuric and tartaric acid, citric acid (17.9%) has been found to be most effective. In addition, citric acid exhibit low degradation of pectin owing to its less dissociation constant (Dalal et al., 2020; Xu et al., 2018).
The process of pectin extraction from orange peel was also optimized by Fakayode and Abobi (2018). For the pectin extraction, first the oil was removed and the pectin was further extracted with the acid hydrolysis technique. The effect of various extraction conditions, i.e., temperatures (80-100°C), time (120-240 minutes), and pH (1.0-3.0) was also studied using 3×5 factorial central composite rotatable design of response surface methodology. 25 g of de-oiled and dried sample was blended in 1000 ml of distilled water and the pH was adjusted by adding hydrochloric acid. The mixture was heated to the desired temperatures with intermittent stirring for the software generated time intervals. The pH was adjusted every 15 minutes and the lost water was replaced. The mixture was rapidly cooled at 40°C in an ice bath and filtered using Whatman filter paper under vacuum. The filtrate was coagulated using equal amount of 95% ethanol and left for different durations (60, 75, 90, 105 and 120 minutes) to allow the pectin to float on the surface. The optimum conditions for the extraction of pectin were a temperature of 93.07°C, time of 117 minutes and pH of 1.60. Benassi et al. (2021) assessed the green extraction methods, i.e., hot water, rapid solid liquid dynamic (RSLD) and microwave-assisted methods for the extraction of pectin and evaluated the yield and quality of extracted pectin. Hot water–based methods were found to be more efficient to obtain high-quality pectin compared to other methods. The pectin yield was further increased (up to 21%) when hot water extraction was assisted by citric acid (pH 1.5). The use of citric acid in extraction also increased the degree of esterification (DE) and the pectin obtained by this method had a DE value of 82.5%. The authors suggested that acidic hot water extraction is the most suitable method to obtain high methoxy pectin, while low methoxy pectin can be obtained using microwave-assisted extraction directly on fresh orange peels. Ultrasound is effectively used for extracting pectin from passion fruit, tangerine and grapefruit peel (de Oliviera et al., 2016, Polanco-Lugo et al., 2019, Wang et al., 2015). Pectin obtained by this method had a higher degree of esterification, higher galacturonic acid content, higher water and oil holding capacity. Use of ultrasound lowered the extraction temperature by approximately 13.3%. The study observed that pectin yield enhanced with increase in microwave power (160 to 400 Watt). Microwave-assisted extraction also yielded a higher degree of extraction in comparison to conventional method (Jiang et al., 2012). In another study, combination of ultrasound followed by microwave extraction was used for pectin extraction from jackfruit peel, and the authors obtained 4% higher yield in comparison to conventional methods (Xu et al., 2018). Ripoll and Hincapié-Llanos (2023) recently published a systematic literature review in which they adopted bibliometric methods for determining the best method for extracting pectin from fruit and vegetable waste. The study concluded that in the past twelve years, acid hydrolysis remains the most widely used method. Other methods like microwave-assisted, ultrasonic and enzymatic methods are also gaining momentum in terms of usage. The study pointed out that in future, use of radiofrequency, ohmic heating and aqueous two-phase extraction appears promising and can be further explored.
1.2.4 Pigments
The waste from fruits and vegetables such as peels, seeds, and pomace, etc., are rich in pigments like anthocyanins, betalins, carotenoids and cholorophylls, etc. These pigments can be extracted by solvent extraction methods or by green extraction methods. The traditional solvent extraction methods utilize a large volume of solvents and take a longer time. The consumption of solvents and extraction time can be decreased by using the novel methods of extraction such as microwave-assisted extraction, ultrasound-assisted extraction, supercritical fluid extraction and enzymatic extraction, etc. These methods also increase the rate of pigment extraction and a 10% increase in yield has been reported for ultrasound-assisted extraction (Sharma and Bhat, 2021). Green solvents such as water, natural oils, ionic solvents, etc., can also be used for their extraction. This section discusses the scientific studies on the pigment extraction.
Sharma and Bhat (2021) extracted the carotenoids from the pulp and peel of two varieties of pumpkin, i.e., Gold Nugget and Amoro F1 of the species Cucurbita maxima using the conventional technique and innovative green extraction techniques, i.e., ultrasound-assisted extraction and microwave-assisted extraction. The pulp and peel of the samples was separated manually, cut into small pieces, freeze dried and ground to a fine powder. This was further extracted with the above-mentioned techniques. In the conventional extraction, 25 ml of mixed solvent containing hexane and iso-propanol in the ratio 60:40 was added to 5 g of pulp or peel sample and the extraction was repeated four times until no visible yellow color was obtained in extract. To achieve the phase separation and to eliminate the traces of isopropanol the extracts were washed with equal volumes of 0.1% NaCl. The extracts were placed in hot air oven (45°C) to evaporate the solvent to 50 ml. The extract was stored at -20°C for further estimations. For ultrasound-assisted extraction, 50 ml of corn oil was added to 5 g of sample and ultrasound probe of 13 mm was immersed in the sample at amplitude of 20% for 30 minutes. The pulse duration was adjusted to “on” (10 s) and “off” (5 s) mode during the extraction process. The extract was centrifuged at 4500 rpm for 45 minutes to separate the oil and residue and was further stored at -20°C. Microwave-assisted extraction was carried out using 5 g of pumpkin sample and 50 ml of corn oil at 130 W for 30 minutes. The extract was further centrifuged at 4500 rpm for 45 minutes to separate the residue and stored at -20°C. On the estimation of total carotenoids it was found that the highest carotenoid for peel (33.78-38.03 μg/g) and pulp (28.01-32.69 μg/g) in both the varieties was obtained for ultrasound-assisted extraction, followed by microwaves, i.e., 30.78-34.94 μg/g for peel and 26.98-31.067 μg/g for pulp. The level of carotenoids in the innovative green extraction methods was almost double that of conventional extraction, i.e., 16.21-19.21 μg/g for peel and 12.33-15.01 μg/g for pulp. El-Rahman et al. (2019) studied the β-carotene extraction from the orange peel. The orange peels were dehydrated at 50±1°C and ground to powder. The 500 g of dehydrated powder was macerated in 1 L of acetone in the presence of 0.1% ascorbic acid in a blender. The extract was filtered and the residue was again extracted twice with the acetone. The collected crude extract was concentrated in a rotary vacuum drier at 40±1°C, the impurities like oil and chlorophyll was removed by saponification. The concentrated extract was added to a separating funnel and washed twice with 200 ml of methanolic potassium hydroxide solution (100g potassium hydroxide dissolved in 750 ml methanol) and 250 ml of water. Following this, a suitable amount of hexane was added to extract the carotenoids. The major carotenoid in the orange peel was β-carotene and its content was 14.51 mg/100g. These extracts can be used in various food preparations. Kumcuoglu et al. (2014) compared the ultrasound-assisted extraction of lycopene from tomato processing wastes with the conventional methods of extraction. Tomato waste (skins and seeds) was collected from a hot break tomato paste manufacturing plant, dried in a vacuum drier at 40°C for 24 h to moisture content of 4.9%, ground in a hammer mill and the particles having average size of 286.6 μm were used for lycopene extraction. For the conventional extraction 0.8, 1.14 and 2.0 g of dried samples containing 48.80% skin and 51.20% seeds were extracted with 40 ml mixture of solvent containing hexane, methanol and acetone in the ratios 2:1:1 v/v making the final liquid to solid ratios to be 50:1, 35:1 and 20:1. The suspension was agitated continuously in a shaking water bath at different temperatures (20, 40, and 60°C) and times (10, 20, 30, and 40 minutes). On the completion of the extraction, 15 ml cold distilled water was added to accelerate separation and the suspension was further agitated at 1000 rpm and 5°C. This was left undisturbed for 5 minutes and polar layer was separated and used for lycopene determination. In UAE, the solvent composition and liquid solid ratio was similar to the conventional system and for extraction a high-intensity probe system of 200W and 24 kHz, equipped with a H14 Sonotrode was used. The sample and the solvent was added to a 150 ml flask, the flask was put in the constant temperature (5°C) water bath and the ultrasonic probe was immersed in the flask by 7 cm from the top. The extraction was carried out at the ultrasound powers of 50, 65 and 90 W for 1, 2, 5, 10, 15, 20, and 30-minute runs. In the conventional method the highest yield (93.9±0.56 mg/kg) of lycopene was obtained when the extraction was carried out at 60°C for 40 minutes at a solvent to sample ratio of 50:1 v/w. In UAE, the highest lycopene concentration (89.9±0.87 mg/kg) was obtained when the extraction was carried out at 90 W and 30 minutes using 35:1 v/w of solvent to sample. The difference in the yield of lycopene was very small in both the extraction methods; however, UAE employed less time, less solvent and low temperature to reach the same rate of extraction. Catalkaya and Kahveci (2019) reported that an extraction process combining enzymatic and solvent extraction of the tomato waste can be employed to produce lycopene from tomato paste production waste. The pre-treatment of 4 g of ground tomato waste (peels and seeds) mixed with 27.2 ml of distilled water, 0.8 ml (0.2 ml/g) of suitable enzyme mixture, i.e., cellulolytic and pectolytic enzymes at the enzyme to enzyme ratio of 1, incubated at 40°C for 5 h, followed by the extraction with ethyl acetate at the solvent to substrate ratio of 5 ml/g and extraction time of 1 h produced oleoresins with the highest lycopene (11.5 mg/g) concentration and red color intensity. These oleoresins also had the highest phenolic compound concentrations and antioxidant properties.
Betalains are a class of red and yellow pigments derived from tyrosine. These are abundantly found in beetroot. The ultrasound-assisted extraction method was used by Fernando et al. (2021) to extract betalains from red beetroot waste. A combination of ethanol/water-based solvent mixtures was used for extraction and was found to be better than individual solvent usage. The sample solution was sonicated at 44 kHz for 30 min at 30°C. The nominal power and energy density in the study was 35W and 252 J/mL. The amount of betalains so extracted was much more than from pomace (beetroot waste). Extraction of beetroot pomace from pomace powder was optimised by Kushwaha et al. (2017). A solid to liquid ratio of (1:15) was found to be suitable for extraction. Maximum yield was obtained at a temperature of 50ºC for 10 minutes at a pH of 2.5. Microwave-assisted extraction was also used for extraction of pigments from beetroot peels. The microwave power of 224.61 MW, pH of 5.2 and time of 57 seconds were the optimised conditions obtained when citric acid was used as solvent. With ethanol as a solvent, the optimised conditions varied with microwave power being 384.25 MW, pH of 4.74 and time of 74.91 seconds (Singh et al. 2017). Hernández-Aguirre (2021) used deep eutectic solvents (magnesium chloride hexahydrate and urea in different proportions) to extract red and violet betalains form beetroot waste. A ratio of 2:1 (magnesium chloride hexahydrate: urea) was found best for extraction and recovery of betalains. The extracts such obtained were 75% more stable than aqueous beet extracts and were stable for a period of 150 days under visible light and 340 days in amber vessel storage. The aqueous extracts exhibited alteration from violet colour just after 5-7 days. Enzyme-assisted extraction can be also be used for recovery of betalains from beetroot waste. Lombardelli et al. (2021) used a mixture of cellulases (37%), xylanases (35%) and pectinases (28%) for extraction of betalains from unsold beetroot. A dosage of 25 U/g of enzyme mix, temperature of 25ºC and processing time of 240 min was found to be suitable for pigment extraction. Thirugnanasambandham and Sivakumar (2017) extracted betalains from dragon fruit peel. The authors used microwave assisted extraction for the same. The experiment so conducted was optimised using response surface methodology. The optimised conditions suitable for the extraction of betalains from 20 g dragon fruit peel were a temperature of 35ºC and time of 8 minutes. Using these conditions, 9 mg/L of betalain was obtained. Utpott et al. (2020) tested the suitability of encapsulating betalains from red dragon fruit (Pitaya). Pitaya fruit peel was used for extraction of mucilage and mixed with maltodextrin for microencapsulation using spray drying. The yield from such matrix was obtained to be 16-25% owing to the low solid content. The incorporation from peel extracts enhanced betalain retention by 7%. Active packaging involving betalains extracted from waste have been studied. Rodríguez-Félix (2022) tested the suitability of ultrafiltered betalain extract obtained from beet baggase for use in preparation of active packaging. It was found that the average degradation temperature for all zein-betalain films was 313ºC. With the increase in concentration of betalain, the hydrophobicity was enhanced. Smoother films were obtained by using ultrafiltered betalains in comparison to non-ultrafiltered betalains.
Anthocyanins were water soluble pigments found in the vacuole of plants exhibiting red, purple, blue or black colour depending upon the pH of the system. Anthocyanins were extracted from blueberry skin using various combinations of temperature, sulphur dioxide, citric acid and industrial juice processing enzymes. Enzyme application was least effective for anthocyanin recovery in this study (Lee and Wrolstad, 2004). Al-Shurait and Al-Ali (2022) optimised extraction conditions for solvent type, temperature, time, pH from the peels of eggplant, onion, red cabbage and pomegranate. Maximum extraction was obtained with acidified ethyl alcohol (5% citric acid) at pH 2 followed by acidified ethyl alcohol with hydrochloric acid. Optimum raw material: solvent ratio extraction from onion and eggplant was found to be 1:40 compared to 1:20 for extraction from cabbage leaves and pomegranate peels. Medium stability is an extremely important factor especially when it comes to bioactive compounds. Patras (2019) assessed the stability of anthocyanins obtained from cabbage waste in the presence of other food ingredients. The study included nineteen different compounds for assessment. Tartaric and citric acid influence the stability and colour to the maximum extent. In general, the authors concluded that the overall color changes are due to acids, calcium, magnesium and natrium. Ingredients like honey, glycine, xylitol, lactose and maltose induce smaller colour changes. Anthocyanins extracted from blackcurrant fruit waste was used as a renewable hair dye by Rose et al. (2018). The study utilised the fruit skins obtained as a waste from the fruit pressing industry for extraction of pigment using acidified water. Freundlich isotherm was followed for anthocyanin sorption onto hair. The hair dye has stability even after multiple washes. Anthocyanins extracted from Plinia cauliflora and purple sweet potato peels were used for manufacturing colorimetric indicator films. These films were used to monitor meat freshness. The extraction was done using acidified water solution. Incorporation studies showed that the pigment enhanced molecular spacing in polymer chains indicating incorporation in the film (Capello et al., 2021).
1.2.5 Biofuels
In the changing world order and the current situation of conflict among various countries, biofuels are now not just an alternative to natural petroleum products but they have become the exclusive need of the energy-intensive developing countries. The reserves of petroleum-based fuels are finite and the depleting petroleum reserves also raise concern. It has now become essential to utilize non-conventional sources of energy. Agriculture-dominated economies like India generate a lot of waste from agriculture and food processing. This waste can be successfully used to produce biofuels and can lead to a sustainable energy system. This section discusses the studies carried out by various researchers to develop bio-fuels from different fruit and vegetable wastes. Oil can also be extracted from the seeds of fruit vegetables like sponge gourd (Luffa cylindrical (L.) ROEM), pumpkin (Cucurbita moschata L.), bottle gourd, etc. Sponge gourd is widely cultivated in India and it is sown twice, i.e., mid-February to March and mid-May to July. The crop is usually harvested at the unripe mature stage and is ready for harvesting after 70-80 days of sowing. The average yield is 66-83 quintals/acre. Over-mature and ripe fruits are unfit for consumption and hence are wasted. The fully ripened dry fruits of the sponge gourd are rich in fibre and seeds. The fibre extracted from ripe fruit is used as bath sponge, cleansing agent and for making table mats and shoe soles, etc. (Apnikheti, 2022). The number of seeds in each fruit may vary from 203 to 734 (Khan et al., 2017). The seeds are rich in fat (39.11/100g) and protein (33.38 g/100g) and can be used for oil extraction and the residue can be used for the protein extraction. The oil extracted from its seeds is edible and is rich in unsaturated fatty acids especially linoleic acid (50.1%) (Elemo et al., 2011, Ogunsina et al., 2010) and can also be used for cooking purpose. Adetoyese et al. (2020) optimized the process of bioethanol production from sponge gourd using the Central Composite Design of Response Surface Methodology. The study was divided into two parts. In the first part, dried sponge gourd was milled and sieved (with a sieve having pore size of 1.0 mm) and the effect of various pre-treatments, i.e.,
