Examining the polyphenol content, antioxidant activity and fatty acid composition of twenty-one different wastes of fruits, vegetables, oilseeds and beverages

Abstract

One of the most abundantly available, cost-effective valuable resources that are of all-time concern for minimization and economical re-utilization is food waste, and quantifying the phenolic compounds and identifying the principle chemical constituents will favour their industrial exploitation potential. Water, methanol and ethanol extracts of 21 common food wastes of four different classes (fruits, vegetables, oilseeds and beverages) were screened by determination of their antioxidant activity (measured by DPPH activity, reducing power and phosphomolybdenum method) as well as total phenol, flavonoid and ascorbic acid contents. Further predominant chemical constituents (essential fatty acid composition and elemental contents) of the top four phytochemical-rich food wastes were investigated by GC-MS and ICP-MS. Water was more efficient for polyphenol extraction, and ethanol extracts for antioxidant power. Onion peel, pineapple skin and date seed had the highest phenolic content and antioxidant activity. Radish peel showed the highest ascorbic acid content (48.9 ± 1.5 mg/g). Onion peel emerged as a unique source of flavonoids (> 80%). Onion peel, radish peel and pineapple skin were identified to be the sources of essential fatty acid, i.e., linoleic acid, particularly radish peel being the rich source of alpha-linoleic acid highlighting its potential for human dietary intake or as animal feed. Moreover, the screened polyphenol and unsaturated omega fatty acid-rich food wastes constituted considerable quantities of essential macro-and micronutrients. Our study demonstrates the possibility of recovering large amounts of natural phytochemicals from food wastes as alternatives to synthetics and for industrial applications.

Bioprocessing of pineapple waste biomass for sustainable production of bioactive compounds with high antioxidant activity

“…Golden variety, finding a value of 34.39 ± 0.89 mg GAE/g d.m. Similarly, it is close to that reported by Kuppusamy et al [79] who carried out polyphenol extraction in pineapple peels using different solvents: water, methanol and ethanol, registering 68.3 ± 1.2, 28.6 ± 1.5 and 22.3 ± 0.6 mg GAE/g d.m, respectively. Lourenço et al [80] carried out the encapsulation of pineapple peel extracts that were obtained using a water: ethanol ratio (20:80 w/w), finding a TPC of 29.33 mg GAE/g d.m, value close to reported.…”

Food Service Kitchen Scraps as a Source of Bioactive Phytochemicals: Disposal Survey, Optimized Extraction, Metabolomic Screening and Chemometric Evaluation

“…Other studies with papaya residues also identified higher values for flavonoids compared to phenolic acids [ 55 , 61 ]. Vieira, Pinho, Ferreira and Delerue-Matos [ 37 ] analyzed different parts of chayote and observed a greater presence of flavonoids in the peel (approximately 2 times higher) compared to the pulp; a fact later confirmed by Kuppusamy et al [ 62 ], where FVB peels had higher amounts of flavonoids among twenty-one plant residues. It is also important to highlight that the class of other polyphenols (e.g., pyrogallol, 4-hydroxybenzaldehyde, vanillin) was the third most abundant class in all samples, and that lignans and stilbenes presented values close to 0%.…”

Extraction and characterization of polyphenols from fruits and vegetable waste through green extraction technologies with special reference to antioxidant profile

“…Recently, Kuppusamy et al (2020) observed the polyphenol content, antioxidant activity, and fatty acid profile of 21 different agro‐industrial wastes belonging to oilseed, beverages, fruits, and vegetables. They adapted different extraction solvents for extraction and probed different prominent antioxidant assays to estimate the phytonutrient capacity.…”