Effect of Blanching on Enzyme Activity and Bioactive Compounds of Blackberry

Abstract

The inactivation of peroxidase and polyphenol oxidase and the degradation of phenolic compounds, anthocyanins, and antioxidant activity in blackberry were investigated during blanching in water at 80-90 °C, and in steam, from 0 to 10 minutes. The enzyme kinetics indicated the presence of two isoenzymes with different thermal stability, following two-phase model, in which the reaction rate constant increased with increasing temperature for both the heat labile and heat resistant component. The phenolic compounds also followed a biphasic pattern, indicating a more heat resistant fraction, and the rate constants increased with increasing temperature. For the antioxidant activity and anthocyanins, the first order kinetic model (R2>0.982) indicated an increase in degradation rate constants with temperature, from 0.050 to 0.137min-1 for DPPH, 0.085 to 0.285min-1 for ABTS, and 0.017 to 0.052 min-1 for anthocyanins.

Thermal and nonthermal pretreatment methods for the extraction of anthocyanins: A review

“…Blanching is suitable to be used as a pretreatment process because it could gently soften the outer layer of the plant material to facilitate the extraction process. The effect of blanching as a pretreatment for anthocyanin extraction has been studied by many researchers (Deylami et al, 2016; Noreña & Rigon, 2018). In general, blanching can be categorized into steam blanching, hot water blanching, microwave blanching, or ohmic blanching.…”

Trends in maintaining postharvest freshness and quality of Rubus berries

“…(2011) reported a 47% decline in the antioxidant activity of blackberry as well as 80%, 50%, 64%, and 52% reducing levels of ellagitannins, sanguiin H‐6, cyanidin‐3‐malonyl glucoside, and cyanidin‐3‐glucoside after heat treatment at 95°C. Similarly, the thermal treatment of blackberries at 95°C for 10 min reduced the activities of POD and PPO enzymes as well as phenolic content (Noreña & Rigon, 2018). Hence, heat treatment is not recommended for fresh raspberry and blackberry fruit because of its degenerative implications on anthocyanin content, polyphenols, and marketability during the postharvest period.…”

“…Thermal treatment of blackberries at 90 • C for 10 min decreased the anthocyanin levels as compared to control fruit. The continuous downregulated pattern of 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), DPPH, and total anthocyanins was noted from 0.085 to 0.285 min −1 , 0.050 to 0.137 min −1 , and 0.17 to 0.052 min −1 , respectively, which shows the negative correlation between anthocyanin stability and heat treatment in blackberry (Noreña & Rigon, 2018). Raspberry fruit showed first-order kinetics for the degradation of TPC, AsA, and total anthocyanins in response to the heat treatment at 90 • C for 7 h (Summen & Erge, 2014).…”

“…The pasteurization (75 • C for 15 s) of the frozen berries prior to the storage has shown about 3.61 and 2.81 log decrease in colonies of E. coli and MNV type 1 virus, respectively (Baert et al, 2008). Although the heat treatments have significant implications to downregulate the persistence and transmission of foodborne pathogens, but it also causes the degradation of the nutritional components of Rubus berries such as anthocyanins, ABTS, and DPPH molecules (Noreña & Rigon, 2018). Moreover, the ultrasound-assisted steam treatment was evidenced by texture degradation on the raspberry surface reducing its marketability.…”

The Effects of Sugar, Blanching, and Pasteurization on the Antioxidant Properties of Pineapple Juice

“…Although blanching gave a positive response to the increase in antioxidant activity of pineapple juice, the duration of blanching still had to be limited. The long duration of Blanching could reduce the amount of thermolabile antioxidant compounds such as anthocyanins and several other polyphenolic compounds [21]. According to the results of research by Nurhuda et al, [22] blanching for 5 minutes reduced total anthocyanins.…”