In vitro release kinetics of pine bark extract enriched orange juice and the shelf stability

Purpose - This paper seeks to demonstrate a functional beverage incorporating pine bark which is an unutilized forestry waste, determine in vitro release kinetics of enriched beverages, and antioxidant activities, besides assessing their shelf stabilities.Design methodology approach - Orange juice was enriched with Pinus brutia, Pinus pinea bark extracts, Pycnogenol®. In vitro release kinetics was determined in pH 1.2 and pH 7.4. Ascorbic acid content, pH, titratable acidity, and colorimetric analyses were analyzed monthly for eight months to determine shelf life. Additionally, total phenol contents and radical scavenging activities were analyzed. Subsequently a consumer acceptance test was conducted among 200 participants.Findings - The release of all extracts in orange juices in pH 1.2 were slower than pH 7.4. The release results were fitted to Higuchi square root of time kinetic model with high determination coefficients. Although total titratable acidity values were in agreement with the trend of minor pH changes, prominent losses in antioxidant capacities, ascorbic acid contents and color were observed for the last two months suggesting a shelf life of six months. Female participants and young people had a greater tendency to consume such a beverage. Health concerns and flavor were the primary factors affecting their purchasing decisions.Research limitations implications - Findings of the study demonstrated the effects of fortification with a plant-based extract as a substitute to the present practice of fortifying beverages with vitamins and minerals for a potential future market.Originality value - The paper shows that juices fortified with pine bark extracts show higher antioxidant capacities and ascorbic acid contents compared to the control, thereby providing improved functionality.