Effects of different heat treatments on the antioxidant activity and ascorbic acid content of bitter melon, Momordica charantia

Abstract

This study investigated the effects of different heat treatments, namely boiling, microwaving and pressure cooking, on the reduced ascorbic acid content and antioxidant activity in Momordica charantia extracts. The total antioxidant activity of M. charantia extracts was determined by ferric reducing-antioxidant power and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assays. The reduced ascorbic acid content was estimated by ferric reducing-antioxidant power-ascorbic acid assay and confirmed by high performance liquid chromatography. Regardless of the cooking method, all cooked M. charantia extracts had significantly (p < 0.05) higher total antioxidant activity, radical scavenging potency and reduced ascorbic acid content than the uncooked sample. The decreasing order of reduced ascorbic acid in M. charantia was as follows: microwaved > boiled > pressure-cooked > uncooked. The reduced ascorbic acid in M. charantia strongly correlated with the total antioxidant activity (r = 0.958, p < 0.05) and radical scavenging potency (r= 0.951, p < 0.05). The principle component analysis showed that 87% of the variation in the antioxidant values of M. charantia extracts was attributed to the different cooking methods. Heat treatment either by boiling or microwaving for a short period of time (10 minutes) improved the reduced ascorbic acid content in the M. charantia extract. This study showed that the reduced ascorbic acid could be retained under high temperature and pressure in M. charantia extracts.

Preparation, characterization, and bioactivity of Zingiber officinale Roscoe powder‐based Pickering emulsions

“…The antioxidant power of samples was investigated using a multi‐target approach, given the complexity of the oxidative process (Tables 3 and 4). In this study, the half‐maximal inhibitory concentration (IC 50 ) of the positive control, ascorbic acid, used in the antioxidant assays was comparable to a previous finding 35‐37 . All samples could reduce iron with a potency greater than the BHT positive control with values ranging from 91.21 to 102.50 μmol L −1 Fe (II) g −1 for GDPC2 and GDPC1, respectively, whereas values from 101.87 to 102.63 μmol L −1 Fe (II) g −1 were recorded for 05PE_GDPBIO and 05PE_GDPC1, respectively.…”

“…In this study, the half‐maximal inhibitory concentration (IC 50 ) of the positive control, ascorbic acid, used in the antioxidant assays was comparable to a previous finding. 35 , 36 , 37 All samples could reduce iron with a potency greater than the BHT positive control with values ranging from 91.21 to 102.50 μmol L −1 Fe (II) g −1 for GDPC2 and GDPC1, respectively, whereas values from 101.87 to 102.63 μmol L −1 Fe (II) g −1 were recorded for 05PE_GDPBIO and 05PE_GDPC1, respectively. Relative to ginger powders, analyzing the protection from lipid peroxidation, the following trend was observed at both incubation times: GDPC1 > GDPBIO > GDPC2.…”

Physicochemical characterization, bioactive compounds and antioxidant capacity of bitter melon

“…The vitamin C content found in the fruit pulp was lower than found by Ng & Kuppusamy (2019), of 20 mg 100 g -1 (d.b.) using the methodology of L-ascorbic acid oxidase and analytical curve in HPLC.…”

“…fruits are consumed for being rich in bioactive compounds and antioxidant capacity. Consequently, studies about flavonoids content (Madala et al, 2016), total phenolics (Chung et al, 2016), ascorbic acid (Ng & Kuppusamy, 2019), among others, can validate such properties and provide high additive value to the product, which is also part of the income of families of small rural producers.…”

The antioxidant index and chemometric analysis of tannin, flavonoid, and total phenolic extracted from medicinal plant foods with the solvents of different polarities

“…The ferric reducing power of plant extracts was measured according to Ng and Kuppusamy (2019). Iron (II) sulphate (0–1,000 μM) was used as the standard.…”