Using LAB-fermented whey for developing bioactive edible films based on purple sweet potato flour/potato starch

During edible film production, several processes are carried out to maintain the probiotic viability, increasing its cost. However, fermentation to culture probiotics that will be later used for edible film production may increase their resistance during production, application and storage. Therefore, this study aimed to develop edible films based on potato starch or sweet potato flour and non-fermented or fermented (Lactobacillus rhamnosus) whey solution. Edible films were evaluated for their physical, probiotic survival, antioxidant capacity and structural characteristics after 28 days of storage (4 and 20 degrees C). Selected films were used for covering commercial surimi to evaluate their effect on some quality properties. The edible films presented a moisture content of 12.68-18.97%, colour characteristics according to the powder used in their formulation, and a probiotic count higher than 9-log cycles. The fermentation process improved the stability of antioxidant compounds in edible films during storage and gastrointestinal simulation. According to the handling characteristics, edible films based on potato starch (100%) and potato starch/sweet potato (90/10% and 80/20%) were formulated and applied. Although the consumers well-accepted covered surimi, the probiotic counts were lower than 6-log after storage, values below the threshold required to exert its beneficial effects in humans. Edible films based on LAB-fermented whey solution and sweet potato flour presented a probiotic count higher than 9-log cycles and the highest content of bioactive compounds and antioxidant capacity. Applied edible films to surimi were well-accepted by consumers; however, the probiotic counts were lower than 6-log after storage time. image