The role of natural antioxidants in preventing of age-relating diseases is evident. The vegetable industry generates a large amount of waste, which is a good source of antioxidants. The aim of the study was the investigation of the antioxidant effect of long-term consumption of ethanolic yellow onion husk extract in ageing laboratory rodents. Twenty male Wistar albino rats were divided randomly into two groups (n = 10): a control group and an experimental group that received ethanolic yellow onion husk extract (2 mL/rat diluted with distilled water; activity of 4.44 µmol-equiv. quercetin) for 188 days. Oxygen radical absorbance capacity and ferric reducing antioxidant power assays were used to determine the total antioxidant capacity of the extract, which amounted to 941.4 ± 32.7 µmol equiv. Trolox/g raw material and 167.4 ± 16.4 µmol-equiv. quercetin/g raw material, respectively. Oral intake of the onion husk extract affected the indicators of the antioxidant system of the liver and the brain but not of the blood and plasma, mainly due to elevations in the activity of catalase and superoxide dismutase in the liver by 44.4% and 79.1%, respectively, and in the brain by three-fold and 79.1%, respectively. The availability, cheapness and high antioxidant potential of onion waste qualifies it a good source of functional ingredients and bioactive substances applicable in the food and pharmaceutical industries.

Antioxidants play a very important role in the food industry. Recently, both science and industry have shown substantial preference for natural antioxidants, including searching for antioxidant substances from natural sources without undesirable side effects. The purpose of this study was to evaluate the effect of adding Allium cepa husk extract at a volume of 68 or 34 μL/g of unsalted blanched materials to replace 34% and 17% of the beef broth, respectively, which corresponded to a total antioxidant capacity (TAC) of 44.4 or 22.2 μmol-equiv. Q/100 g meat pté (i.e., 13.42 or 6.71 mg of quercetin/100 g meat pté), on the quality and safety indicators of the developed meat pté. The TAC according to a ferric reducing antioxidant power assay, thiobarbituric acid reactive substances, and physicochemical and microbiological characteristics were determined during the storage of the meat pté. Proximal and UPLC-ESI-Q-TOF-MS analyses were also performed. The addition of yellow onion husk ethanolic extract to the meat pté at both volumes allowed the maintenance of an increased content of antioxidants, which contributed to a decrease in the generation of secondary products of lipid peroxidation for 14 days of storage at 4 ∘C. The results of the microbiological analyses showed that the developed meat ptés were safe according to all indicators of microbial spoilage within 10 days of production. The results supported the use of yellow onion husk extract in the food industry to contribute to improving the functionality of meat products, developing products for a healthy lifestyle, and providing clean-label foods without or with a minimal content of synthetic additives.

Among vegetables, onion and garlic production occupies a leading position worldwide due to their wide usage in various sectors of the food industry. Husk is the main waste from onion and garlic processing. The biological properties of onion and garlic bulbs are well studied, but the husks are not well investigated to date. The total antioxidant capacities of aqueous and ethanol extracts of onion and garlic husks and bulbs were determined by the ORAC method and expressed in μmol equiv. Trolox/g of sample. The husks demonstrated the greatest total antioxidant capacities and significantly exceeded those of the bulbs. Onion husk was the most active, and its total antioxidant capacity was 521.24±11.23 μmol equiv. Trolox/g of sample for aqueous extract and 1206.93±8.37 23 μmol equiv. Trolox/g of sample for ethanol extract. Antioxidant capacity depended on extractant type.

According to the data of the Food and Agriculture Organization of the United Nations, global food losses are about one third of their total output, mainly due to spoilage. Therefore, a search for safe methods of shelf life extension is an important task, especially for products for specialized nutrition. According to literature data, natural antioxidants can be alternative to existing preservatives due to its ability to inhibit oxidation of the main nutrients. Pulp, seeds and peel of quince, apple «Simirenko», feijoa, persimmon, Jerusalem artichoke, white, red and yellow onion were objects of the study. The total antioxidant capacity was determined by Oxygen Radical Absorbance Capacity (ORAC) and Ferric Reducing Antioxidant Power (FRAP) methods and expressed in µmol equiv. Trolox / g of sample and µmol equiv. Dihydroquercetin / g of sample. It was noticed that peels demonstrated higher antioxidant activity, and red onion husk possessed the highest value, which was 722.8 ± 13.9 µmol equiv. Dihydroquercetin / g of sample and 3357.5 ± 42.2 µmol equiv. Trolox / g of sample. It was shown that the use of fruit and vegetable wastes is promising for production of food-grade antioxidants. In addition, the results of the research could facilitate stimulation of rational and efficient environmental management.