Stability of vitamin C in fresh and freeze-dried capsicum stored at different temperatures

Abstract

The objective of this study was to determine vitamin C stability in fresh and freeze-dried capsicum during storage at different temperatures. Fresh capsicum stored at 20°C showed an initial decrease in vitamin C with a minimum peak after 2 days and then increased to a maximum peak after 13 days followed by a gradual decay. In general a gradual decrease of vitamin C was observed in the cases of fresh (i.e. stored at 5, −20, −40°C) and freeze-dried capsicum stored at all temperatures (i.e. 60 to −40°C). The degradation kinetics of vitamin C was modeled by zero and first order reaction and rate constants were estimated. The rate constant increased with the increase in storage temperature, while it was decreased with the decrease of moisture content. At storage temperature 5°C, first order rate constants were observed as 7.1×10 −2 , 7.7×10 −2 , and 4.3×10 −3 day −1 in the cases of samples containing moisture contents 94, 15 and 5 g/100 g sample, respectively.

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“…Similarly, first-order reaction was used for the degradation of vitamin C in cabbage and lettuce (Awagu, Ekanem, Kolo, & Adamu, 2017), cherry juice (Jirasatid & Noipant, 2015) and orange juice (Calligaris, Manzocco, & Lagazio, 2012). The first-order reaction rate constant was determined from the slope and these increased from 9.03Ö10 −8 s −1 to 5.65Ö10 −3 s −1 , when storage temperature varied from 5 o C to 120 o C. Vitamin losses in fresh capsicum at 5 o C and 20 o C were observed as 8.22Ö10 −7 and 1.15Ö10 −6 s −1 as compared to the results found in this study of 9.03Ö10 −8 (at 5 o C) and 4.03Ö10 −6 s −1 (at 20 o C) (Rahman et al, 2015). At refrigerated temperatures, the loss of vitamin C in broccoli was much higher than capsicum, whereas comparable losses were observed at 20 o C. In the case of orange juice stored at 10 o C, the rate constant was observed as 4.63Ö10 −7 s −1 (Calligaris et al, 2012).…”

“…In most of the isothermal experiments, an initial lag period was observed and the above equation was modified with an intercept rather forcing the intercept to zero as Equation 1 (Rahman et al, 2015). The experimental data was fitted with a linear equation with an intercept as follows:…”

Impact of sprouting on the degradation kinetics of color and vitamin C of onion powder packaged in different packaging materials

“…Degradation of vitamin C in raw (Figure ) and sprouted (Figure ) onion powder from PRO‐6 variety stayed in good agreement with first‐order kinetics with correlation coefficient R 2 ranging from 0.92 to 0.94 in different packaging materials during storage. First‐order kinetic model was also best fit for vitamin C degradation in case of freeze dried capsicum (Rahman et al, ). The degradation kinetics of both raw and sprouted onion powder samples during storage was assessed and respective rate constants and half‐lives were determined (Table ).…”

“…Values are means ± SD of triplicates and means were significant at p < 0.05. to 0.94 in different packaging materials during storage. First-order kinetic model was also best fit for vitamin C degradation in case of freeze dried capsicum (Rahman et al, 2015). The degradation kinetics of both raw and sprouted onion powder samples during storage was assessed and respective rate constants and half-lives were determined (Table 4).…”

Kinetics of nutrient change and color retention during low‐temperature microwave‐assisted drying of bitter melon ( Momordica charantia L.)

“…Its vitamin C content of about 40 mg/100 g of fresh fruit is comparable to those in other fruits, such as strawberry. Vitamin C is prone to degradation during processing and storage, due to various factors, including temperature, light, and air oxidation (Rahman et al, ; Santos & Silva, ). Therefore, vitamin C is often used as an index of nutrient quality in food processing research.…”