Influence of microwave processing on the bioactive compounds, antioxidant activity and sensory acceptance of blackberry jelly

Abstract

The purpose of this study was to evaluate the effect of microwave and microwave combined with vacuum on the nutritional and sensory characteristics of blackberry jelly, in order to verify if they are actually more viable methods of processing when compared to the traditional process in open pan. Ot was verified that the processing methods studied did not influence the sensory characteristics of the obtained jelly, however, it was observed that the microwave processing, in particular low power microwave without vacuum, promotes smaller nutritional losses in the blackberry jelly. The jellies processed in low-power microwave without vacuum stood out from the others presenting the highest antioxidant activity by DPPH (2095.19 g f.w./g of DPPH) and ABTS method (21.81 μM trolox/g), the highest total phenolic content (504.58 mg GAE/100 g) and one of the highest ascorbic acid content (33.72 mg ascorbic acid/100 g). The jelly processed in high-power microwave without vacuum, stood out to have the highest antioxidant activity by the beta-carotene method (84.20% protection). On relation to the anthocyanins content, the jellies processed by vacuum microwave (low and high power) were highlighted because they presented the highest levels (16.25 and 15.03 mg of cyanidin equivalent 3 glucoside/100g, respectively).

Microwave assisted drying and extraction technique; kinetic modelling, energy consumption and influence on antioxidant compounds of fenugreek leaves

“…The antioxidant activities (DPPH activity) of the samples were determined by the method described in literature (Barkat et al, 2018;Curi et al, 2019). In this method, sample (0.5 mL) material in the form of extract obtained from Microwave and methanol extraction method added in methanol-based DPPH (4% w/v) solution; subsequently vigorous shaking of the mixture was carried out.…”

A promising natural purple batter system with antioxidant activity for vacuum fried breaded shrimp

“…The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging ability of the PSP breaded shrimps extract was determined using a standard method (Park et al, 2012;Curi et al, 2019). Anthocyanin extract (4.0 mL) was mixed with 4.0 mL of DPPH (0.0178 mM), measured quickly, then kept at room temperature for 30 min before measuring the absorbance at 517 nm.…”

Influence of microwave vacuum drying on the effective moisture diffusivity of seedless white grapes

“…Microwave vacuum drying combines microwave and vacuum drying techniques and has advantages such as high drying rate, use of low temperature, high efficiency, and operational safety. While microwave provides a uniform heat source for vacuum drying, reducing the overheating of parts that do not require heating, the vacuum environment allows foodstuff to be dried under a relatively low temperature, which facilitates the preservation of their color, fragrance, flavor, and bioactive substances (Ozcan-Sinir et al, 2019;Curi et al, 2019). So far, microwave vacuum drying has been recognized as the most promising method for the preservation of fruits and vegetables.…”