Freeze-dried persimmon peel: A potential ingredient for functional ice cream

Abstract

The peels are considered part of waste products, which are generally discarded. The use of persimmon peel is associated with its phenolic content, dietary fibers, minerals, and pectins. The main objective of this study was to evaluate changes in antioxidant activity, total phenolic contents (TPC), and color parameters of persimmon peels after freeze drying (−85 °C for 24h), vacuum oven drying (45 °C for 12h), oven drying (50 °C for 12h) and microwave oven drying treatment (900W for 10s). In the next step, the functional ice cream was prepared and studied by adding dried persimmon peel powder (DPPP). Various properties of the resulting ice cream at 4 levels of DPPP addition were investigated. The results showed that the highest value of L*,a*,and b* parameters were in the freeze-dried sample. There was a significant difference in the TPC of samples that dried by different methods (p < 0.05). The highest amount of TPC was observed in the freeze-dried sample (673 ± 2.0 mgGAE/100g) and the lowest one was observed in the oven-dried sample (352 ± 0.5 mgGAE/100g). The highest value for IC50 (concentration of the antioxidant compound that is necessary for the DPPH radical concentration to reach 50 % of the initial value) was in the sample dried in the oven, following the vacuum oven, microwave, and the lowest value was in the freeze-dried sample. DPPP produced by the freeze-drying method was applied in ice cream formulation at different levels (0–3 %wt.). By increasing the amount of DPPP from 0 to 3 %, the overrun and L* decreased and a*, b*, hardness, and melting resistance of ice cream increased significantly (p < 0.05). Based on our findings, DPPP has the potential to be applied as an added-value ingredient in the ice cream industry to improve the functional characteristics of its products.

Keywords

• Persimmon peel
• Ice cream
• Melting resistance
• Natural colorant
• Food waste