Characterization of Grape and Apple Peel Wastes’ Bioactive Compounds and Their Increased Bioavailability After Exposure to Thermal Process

Abstract

ABSTRACT80% of the grape harvest is used in the winemaking industry, resulting in huge amounts of waste which are still rich in phenolic compounds, while the same percentage of polyphenols are found in apple peel, whose total antioxidant capacity is five-to-six-fold higher than that of apple flesh. The aim of this research is the characterization of grape and apple peels waste, before and after the thermal treatment (10 minutes, 80°C), with respect to its bioactive compounds to evaluate their potential enhancement with respect to bioavailability. Based on the obtained results, the highest antioxidant activity and phenolic content was exhibited by thermally processed redgrape waste. After the thermal treatment, the caffeic acid 4-O-glucoside increased with a 27% in apple waste. As a conclusion, the grape and apple peels waste can be exploited for their bioactive compounds after the thermal process, whose bioavailability increased and can be added in food formulations as health promoting products.

Thermal Processing for the Release of Phenolic Compounds from Wheat and Oat Bran

“…The strong antioxidant capacity of thermally processed wheat bran and oat bran (considering the increased content of ferulic acid, apigeninglucoside, and avenanthramides), may underline the possible correlation between the antimicrobial effect and antioxidant capacity exhibited by the presence of phenolic compounds. The S.aureus was the most sensitive bacterium to the tested extracts, a fact which was in agreement with our previous work [27,28]. WBTP registered an MIC of 1.875 (mg/mL) against E. faecalis, whereas OBTP showed The phenolic composition of WB (Table 2) improved after thermal treatment, and each individual phenolic compound had a significant relative percentage increase versus fresh samples (ferulic acid +39.18%, caffeic acid +68.15; vanillic acid +95.68%, dihydroxybenzoic acid +31.54%, apigenin-glucoside +71.96%; p-coumaric acid +71.91, sinapic acid +49.65).…”

“…The strong antioxidant capacity of thermally processed wheat bran and oat bran (considering the increased content of ferulic acid, apigenin-glucoside, and avenanthramides), may underline the possible correlation between the antimicrobial effect and antioxidant capacity exhibited by the presence of phenolic compounds. The S. aureus was the most sensitive bacterium to the tested extracts, a fact which was in agreement with our previous work [27,28]. WBTP registered an MIC of 1.875 (mg/mL) against E. faecalis, whereas OBTP showed an MIC of 3.75 (mg/mL) toward the same strains.…”

“…The thermal processing of bran is one of the most practical methods that increase its beneficial effects on human health [1,24,25]. Thermal processing enhances bran's solubility by making the micronutrients bio-available [26], reducing their complex structure [27,28], and decreasing the content of some inhibitory factors [1]. Previous studies on cereal products have presented that thermal processing contributes to the cell wall and cellular constituents' breakdown through the release of the bound phenolic acids [29].…”

Whole Grains and Phenolic Acids: A Review on Bioactivity, Functionality, Health Benefits and Bioavailability

“…In the Li et al (2007) study [ 160 ], the baking of purple wheat bran at 177 °C for 20 min did not influence the total phenolic content in the processed samples. Heat treatment (80 °C, 10 min) enhanced the total phenolic content and the antioxidant activity [ 161 ] by an increased bioaccessibility of the phenolic compounds [ 162 ]. Considering the oat groats experimental study of Bryngelsson et al (2002) [ 163 ], steaming (100 °C, 1 h) and flaking (100 °C, 20 min) reduced caffeic acid, but increased ferulic acid and vanillin, whereas autoclaving (100–120 °C, 2.4 bar, 16 min) increased contents of vanillin, ferulic and p -coumaric acids.…”

Chitosan Coating Applications in Probiotic Microencapsulation

“…Nowadays, there is an increase in functional probiotic food demand, as well as waste-derived bioactive compounds re-utilization [1][2][3][4][5][6][7][8], based on the consciousness of consumers regarding their health potential [9,10]. Considering the IndustryARC report [11] from 2018, the global probiotic market is estimated to experience a compound annual growth rate of 5.6% through 2020.…”