Physical and biochemical qualities of pressurized and pasteurized longan<br>juices upon storage

Abstract

The physical and biochemical properties of pressurized longan juice at 500 MPa; 25°C for 30 min and pasteurized juice at 90°C for 2 min were investigated during storage at 4°C for 4 weeks. Color parameters indicated that although enzymatic degradation in pressurized longan juice was the primary cause of lower L parameter (lightness) during storage, its magnitude was apparently lesser than browning caused by Maillard reaction in pasteurized juices reflected by b* (yellowness) and BI (browning index) parameters. The results of residual enzymes showed that during storage, polyphenol-oxidase had greater rate of degradation and was more resistant to pressure than peroxidase. The bioactive components like ascorbic acid in pressurized juice exhibited higher reduction during storage than that of pasteurized juice. However, residual ascorbic acid in pressurized juice was still higher than that thermal treated juice throughout the storage period. The other bioactive components in pressurized juice were also gradually degraded during storage by 71%, 66%, 28% and 37%, while in pasteurized products substantially reduced by 60%, 69%, 23% and 35% for gallic acid, ellagic acid, total phenols and antioxidant activity (DPPH assay), respectively.

Alteration of antioxidative properties of longan flower-honey after high pressure, ultra-sonic and thermal processing

“…This finding concurs with Šarić et al(2012), who demonstrated that acacia and multifloral honeys displayed a significant curtailment in total flavonoids, total phenolics and antioxidant activity (DPPH and FRAP methods) after one year of storage at room temperature. Similar outcomes have been previously established by our study in other products, such as longan and pennywort juices and(Chaikham & Apichartsrangkoon, 2012b;Chaikham, Chunthanom, & Apichartsrangkoon, 2013;Chaikham, Apichartsrangkoon, & Seesuriyachan, 2014).…”

Pytochemical profile and antioxidant activity of chiltepin chili (Capsicum annuum var. glabriusculum), Sonora, Mexico

“…Finally, gallic acid was present in higher amounts in the control sample (80.1 µg g −1 ), with 3.8% higher amounts in the irradiated and 9.7% in the pasteurized samples, indicating the negative effect of processing on that compound. Similar results were obtained by Kumari and Khatkar (2019) when they verified a reduction in the gallic acid content after pasteurization (90 °C for 1 min) of aonla juice; and also by Chaikham et al (2014) after they pasteurized longan juice (90 °C for 2 min). The reduction in the gallic acid content in the irradiated samples of the feijoa pulp can be related to the fact that this compound has antioxidant activity, donating H atoms of the phenol groups to the free radicals formed during irradiation (Roidoung et al, 2016).…”

Effects of germinated and nongerminated rice grains on storage stability of pressurized purple rice beverages with Lactobacillus casei 01 supplement

“…Similarly, Keenan et al (2010) found that, total phenols and antioxidant capacity (DPPH) in pressurized fruit smoothies decreased by 33.9% and 29.4%, respectively, upon storage at 4°C for 30 days. Later, Chaikham, Apichartsrangkoon, and Seesuriyachan (2014) pressurized longan juice at 500 MPa/25°C/30 min and found that total phenols and antioxidant activity (DPPH assay) decreased by 28% and 37%, respectively, on storage at 4°C for 4 weeks. Decrease in anthocyanins and total phenols by 29.76% and 16.22%, respectively, was also found in pressurized (at 600 MPa/4 min) cloudy strawberry juices after storage at 4°C for 6 month (Cao et al, 2012).…”