Polyphenol oxidase (PPO) causes the browning reaction in fruits and vegetables and deteriorates the quality. Thermal treatment for enzyme inactivation may result in defects as opposed to high pressure CO2 (HPCD) processing. In this study, the changes in activity, dissociation, aggregation and conformation of purified PPO from thermal and HPCD treated juice were investigated. HPCD exhibited inactivation of PPO at 55–65 °C whereas thermal processing alone at the same temperature resulted in PPO still showing activity. Under thermal treatment at 25 and 65 °C, the browning degree was higher (0.39 and 0.24) than for HPCD-treated juice (0.23 and 0.12). Fluorescence and circular dichroism spectral results indicated that HPCD induced large decreases in intensities, revealing a rearrangement of the secondary structure and destruction of the native configuration of the PPO molecule. The particle size distribution (PSD) pattern revealed structural modification leading to initial dissociation and subsequent aggregation of PPO after HPCD treatment. Polyacrylamide gel electrophoresis (PAGE) analysis exhibited that molecular size of protein was 40 kDa. In conclusion, the HPCD method was found to be more effective than thermal treatment to inactivate PPO. Structural modifications provided better insights into the phenomena of activation and inactivation of PPO.
16 April 2024 in Journal of Food Processing and Preservation
The coriander plant (Coriandrum sativum L.) is well known for its antibacterial and antioxidant properties since it contains a considerable number of bioactive compounds. This property encourages the use of coriander in food because it has many health benefits and preserves food longer. The current study’s objective was to demonstrate the extraction of coriander’s three fractions (leaves, flowers, and seeds) using microwave drying and ultrasonic assistance, in order to identify its distinct functional components. After microwave drying, the highest amounts of ash, fat, fiber, and protein with values , , , and , respectively, were observed in coriander seeds. Among macro- and microminerals analyzed, contents of Ca and Mg were found highest in coriander leaves, with values and mg/100 g, respectively, whereas Fe, Zn, and Mn were found highest in seeds with values , , and mg/100 g. Ultrasonic-assisted ethanolic extracts of microwave-dried coriander leaves presented significantly high ( ) total phenolic contents ( mg gallic acid equivalent/100 g), total flavonoid contents ( mg quercetin equivalent/100 g), and total antioxidant activity (
Supplementation with red raspberry enhanced hepatic antioxidant defense, modulated gut microbiota, improved intestinal barrier function and alleviated ethanol-induced liver injury in mice.
The bitter gourd (Momordica charantia L.), has been remained a well-known ethnic medicinal vegetable, used traditionally as a pharma food to obtain a plenty of pharmacological benefits. However, which fraction of fruit is most effective for provision of bioactive components, has been remained undiscovered yet. This study examined the chemical composition, phytochemicals and antioxidant activities of peel, flesh, and seeds of bitter gourd. Our results showed that fat (3.50 ± 0.03%) and protein (3.40 ± 0.06%) content were found to be significantly (P < 0.05) high in bitter gourd seed powder (BSP), whereas ash (6.26 ± 0.06%) and fiber (5.46 ± 0.10%) in bitter gourd peel powder (BPP). Microminerals including Fe, Zn, Cu and Mn were found significantly (P < 0.05) high in BSP, with values 3.95 ± 0.05, 4.92 ± 0.04, 2.44 ± 0.04 and 1.32 ± 0.20 mg/100 g, respectively, whereas, macrominerals, Ca (74.90 ± 0.60 mg/100 g) and Mg (52.59 ± 0.20 mg/100 g), in bitter gourd flesh powder (BFP). Total phenolic content (27.78 ± 0.95 mg GAE/100 g), total flavonoid content (12.18 ± 0.08 mg QE/100 g) and total antioxidant activity (16.87 ± 0.11 mg trolox/100 g) was highest in BSP. However, BFP exhibited the greatest total carotenoid content (93.45 ± 0.40 mg/100 g) and β–carotene content (41.72 ± 0.15 mg/100 g). HPLC analysis revealed that all fractions of bitter gourd were loaded with bioactives, as naringenin and catechin were highest in BFP, epicatechin, ferulic acid, kaempferol and p-coumaric acid were highest in BPP, whereas, chlorogenic acid, caffeic acid, gallic acid and apigenin were highest in BSP. As compared to BFP and BPP, BSP exhibited the high concentration of important bioactive components, therefore instead of discarding these waste by-products of bitter gourd could be utilized as source of bioactives.