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This research was carried out to study phytochemical profile, in vitro antioxidant capacity, reducing power, anti-hyperglycemic, anti-inflammatory activities and simulated gastrointestinal digestion of 7-day old cereal sprouts: spelt wheat 'Nirvana' (WSSpe), wheat 'Simonida' (WSSim), oat 'Golozrni' (OSG) and oat 'Jadar' (OSJ). OSG expressed significantly higher (P ≤ 0.05) total phenols (TPC) and flavonoids content (TFC), antioxidant capacities (DPPH and ABTS assays) and reducing power (EC = 2.12 mg/ml; EC = 0.87 mg/ml; EC = 12.24 mg/ml) as well as anti-hyperglycemic activity (EC = 0.96 mg/ml). WSSpe had the highest content of chlorophyll (131.23 mg/100 g) and carotenoids (22.84 mg/100 g). WSSim possessed the most potent anti-inflammatory activity (2.71 mg/ml), though not significantly different from OSG (2.77 mg/ml). The in vitro simulation of gastro-intestinal digestion showed higher release of phenolic compounds in intestinal than in gastric fluid.

In order to deactivate the health properties of bioactive compounds, they need to withstand the effects of food processing, their potential release from the food matrix, and remain bio-accessible in the gastrointestinal tract. Bio-actives from different plants are prone to oxidative degradation, and encapsulation is an effective method in improving their stability. In the present study, red pepper waste (RPW), a by-product of vegetable processing industry, was encapsulated in whey protein using spray and freeze-drying techniques. The aim was to evaluate the effects of in vitro gastrointestinal digestion on the release and bioactivity of encapsulated bio-actives, after each digestion step. The results showed that the release of phenolics and carotenoids, as well as antioxidants, anti-hyperglycemic, and anti-inflammatory activities are influenced by pH and intestinal fluid, with pH 7.5 exhibited at higher levels. There was a rapid initial release of carotenoids from whey protein matrices, while a more gradual increase of phenolics was observed, reaching around 50% for both encapsulates first at 6 h and 37 °C, and small intestine conditions. The encapsulation of RPW demonstrated a protective effect against pH changes and enzymatic activities along digestion, and contributed to the increase in bio-accessibility in the gut. Also, the results suggest that encapsulation is an efficient method for valorization of bio-actives from RPW, with improvements in nutrition, color, and bioactive properties.

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Research background: The aim of this work was to evaluate utilization of sweet potato peel as a source of bioactive compounds. The effect of solvents (acetone and acetone/ethanol mixture) on extraction efficiency of total carotenods and phenolics from sweet potato flesh tuber and peel, and antioxidant activity were investigated. SPP extract standed out in terms of antioxidant activity and was choosen for encapsulation by spray and freeze drying techniques. Experimental approach: Encapsulation is an effective method to improve phytochemical stability by entrapping the core material with a coating agent. In this study, spray and freeze-drying techniques were applied for improving the stability of bioactive compounds (carotenoids and phenolics) using whey protein as a coating material. The main advantages of applied techniques over the other encapsulation techniques are simplicity, continuity, effectiveness, availability, and applicability. Results and conclusions: Physicochemical characteristics revealed that spray drying resulted in the formation of lower size particles, better flowing properties, and encapsulation efficiency of carotenoids. The retention of encapsulated and non-encapsulated bioactive compounds was monitoring during storage at daylight and dark conditions. Storage conditions affected the carotenoid retention, whereas daylight exhibited the higher degradation rate for all samples. Phenolic compounds exhibited higher retention for all investigated samples. Degradation kinetic parameters suggest the longer shelf life of spray dried encapsulates and potent method for bioactives stabilization. Novelty and scientific contribution: This study demonstrates that the spray drying technique and utilization of sweet potato peel have big potential in functional additives development, with improved nutritional, color and bioactive properties.