Conversion of Fruits and Vegetable Waste into Bio-Active Compounds

Mohamed Sakil. A1, Shaliha. A1, R. Dakshayani2 and Dr. R. Jagan Mohan3
 
INTRODUCTION:
Food waste can be classified as a non-edible part of the food supply chain. Food waste occurs throughout the food system, including waste from farms, processing lines from industries, storage, transportation and household wastes. Generally, food waste may be of several types: meat and poultry wastes, fruits and vegetable wastes, dairy wastes, cereals, legumes and oilseed wastes. Apart from various types of waste let us focus on fruits and vegetable waste, their conversion into value-added products and the challenges faced in the conversion process. At the ménage position, food is being wasted in nearly1.3 a billion tonnes each over the world. The most food waste-producing countries globally include India, China, the USA and Brazil. Food waste will increase environmental, health and also profitable issues. This is ghastly for the growing world. There are various sources of food waste. They are Animal excrement, which is usually categorized into three types: Meat-based products, Marine-based products and Milk-based products. There are four types of vegetable waste subtypes: grains (such as brewing grains, wheat bran, and rice external layer), Roots and stolons (e.g. potato skins, sugar beet), iii. Legumes and oilseeds (which include sunflower seeds, soybean seeds, as well as pressed olive residue), Veggies and fruits (orange rind, grape pomace, apple skin, tomato pomace etc.).  To efficiently convert this food waste into value-added products, there is a need to introduce methods and techniques. These food waste sources are rich in various bioactive compounds including biofuel, bioenergy, antibiotics, and enzymes which are discussed below.

CURRENT CONVERSION STRATEGIES:
Most foods waste is  burned as traditional energy or dumped in landfills. Food waste would be suitable for fermentation to produce biomass because it is biodegradable and contains a lot of water. The yield of short-chain fatty acids during anaerobic fermentation causes the pH to decrease, which is  the main barrier to the anaerobic fermentation of food waste. It prevents the development of organisms that produce methane. By employing an integration or alternative strategy, we could possibly resolve this issue. Research and development efforts are being made to turn non-uniform food waste into a variety of value-added products that are also biologically and economically viable food waste organisms. The creation of conversion strategies results from it. Brazil, the United States, India, China, and Japan collectively produce 70% of the world’s citrus crop. 50 percent of the weight of citrus fruits is made up of the skin. More than 31.2 million tonnes of citrus are processed, yielding an estimated 15.6 million tonnes of rind from the 94.8 million tonnes of citrus produced globally. Citrus skin contains a number of key chemical components, including sugar, hemicellulose, cellulose, glucans, and linalool. Pectin enzymes, pectin, complex carbohydrates, bio-ethanol, Timonen, methane and succinic acids are all products of citrus peels. An important chemical with antiviral, anticancer and anti-inflammatory properties is orange oil. The majority of the mangoes used in various products come from India. Skins and holes, which make up 30-55% of mango are the main waste generated in the mango processing industry. Mango skin contains polyphenols, cellulose, hemicellulose, carotenoids, long chain amino acids, pectin and fatty acids. Mango skin has been used in the production of pectin, phenolic compounds, ethanol, pectinase, cellulase, lactic acid and biogas. The major bioactive compounds isolated from mango rind were flavanols (epicatechin gallate, flavon-3-ol).

SEPARATION OF BIOACTIVE COMPOUNDS FROM AGRICULTURAL AND FOOD WATES:
Alkaloids, dyes, polyphenols and antibiotics are examples of bioactive molecules. Food waste could be used to recover biopolymers like fibres, proteins, polysaccharides, and lipids. These bioactive compounds have biological effects on the body, including antioxidant, anti-diabetic, anti-inflammatory, cardiovascular and anti-cancer effects. The water treatment, biomedical, energy, and food industries all use biopolymers. Physical, chemical and biochemical processes are required to separate the active components of food waste from the core matrix.

VALUE ADDITION – FOOD AND KITCHEN WASTE:
Home and food scraps could be used to generate a range of products with added value. These include enzymes, high fructose syrup, films, levulinic acid, mushroom growing, acids including dietary supplements, pigments, single-cell protein, sugar, vermilion organic manure, wax esters, as well as xanthan. They also include activated charcoal adsorbents, antioxidants, bioactive substances, bioethanol, bio butanol, biodiesel, biogas, and bioelectricity.

ANTIOXIDANTS:
Antioxidants are substances which facilitate the evaporation of molecules to produce free revolutionaries. As a result, these substances serve as essential additives in edible products and in fuels as oxidative inhibitors. Additionally, antioxidants decrease the risk of few diseases in humans. These cause people to consume more naturally occurring antioxidants, which are better for their health. The production of antioxidant compounds uses a variety of food industry wastes, such as peel extract, seed pods and more. Numerous antioxidant substances, like ascorbic acid, α-tocopherol and rosemary extract, were currently utilized by food sector, primarily by way of additives which were approved by regulations. However, today’s biggest challenge is finding components with the similar capability in waste, demonstrating its functionality as well as safety before introducing them into the food system. Any by-product, such as overripe berries, unsuitable fruit, peels, pomace and seeds, can be viewed as a valuable source of new antioxidant food additives.

ENZYMES:
Amylases: This type of enzyme converts starch into less complex sugars like maltose, maltotriose and glucose. Recent studies have shown that the activity of Aspergillus Niger routinely uses banana skin for the assembly of amylases.

Cellulase: Cellulase an endocellulase, exocellulase and -glucosidase complex enzyme. The sequential actions of those enzymes result in the complete hydrolysis of the cellulose. These enzymes are essential for the hydrolysis of biomass. The analysis found the potential use of paper and soybean hulls as supports in Aspergillus Niger’s solid-state fermentation to develop cellulase. The soybean hulls utility produces inclined volumetric productivity in a small span of, which can improve the overall economics of the process.

Protease: Protease is an enzyme that speedup the protein hydrolysis. Its application was widely available in medicinal, food and cleansing agent ie., detergent industries. Waste bread slices were used for protease production by Aspergillus awamori by a packed-bed reactor. Research indicates the capability of wasted bread being possible for the production of protease.   Bread is a perfect substratum for solid-state fermentation which forms major garbage in numerous countries. Presently, these wasted breads were dumped in landfilling that leads to production of methane by anaerobic digestion. Methane deliberates 21 times higher heating potential when compared to CO2. Thus, waste utilization and value addition look promising with respect to economic and ecological benefits.

QUERCETIN: A widespread flavonoid found in fruits and vegetables is quercetin, frequently added as a supplement to foods and drinks. These substances are adequately used to treat conditions like cancers of the kidney, colon, breast, etc. One of the main waste products from processed onions may be onion processing waste. A method for turning onion skin scraps into quercetin was developed. Cellulase, pectinase, and xylanase were used in a cocktail to enzymatically saccharify the waste onion skin. The extraction of quercetin might be increased 1.61 times by enzymatic saccharification. For the simple separation and purification of quercetin, a completely unique magnetic matrix was employed.

Table 1: Fruits and vegetables by-products – sources and Extraction techniques

CONCLUSION:

India being the second largest producer of fruits and vegetables lacks in post-harvest handling. Though during processing, it produces numerous by-products which has the potential to make into use for various application. The bioactive components extracted from by-products of fruit and vegetable processing sector is now becoming trend and reduce effluent treatment difficulties. It also effects in reduction of carbon foot printing to some extent. Thus, waste utilization and value addition for large scale application has to be strengthened and also the regulations have to be enforced for the same.  This also leads to application in new product development with enriched nutrient, structural modification of food, minimize waste from Fruits and vegetables Industry, possibly 3D printing of food/plate and to formulate targeted drug/ nutrient delivery system using nanotechnology.  

1 III Year B. Tech, Food Technology, National Institute of Food Technology, Entrepreneurship and Management, Thanjavur.

2 Research Scholar, Food Science and Technology, National Institute of Food Technology, Entrepreneurship and Management, Thanjavur.

3 Professor and Head, Department of Food Product Department, National Institute of Food Technology, Entrepreneurship and Management, Thanjavur.

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