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In this study, different solvents were screened for the extraction of phenolic compounds from brown seaweed (Padina tetrastromatica). Among the methods, 50% (v/v) methanol gave maximum yield having higher phenolic content with antioxidant and antimicrobial activities. The methanol free crude extract was used as a natural preservative for chilled stored tilapia by giving dip treatment at different concentrations as control (T0), 0.5% (T1) 1% (T2) 1.5% (T3), and 2% (T4) (v/v) before chilled storage. Sampling was done on the 0th, 7th, 14th, 17th, 21st, 23rd, and 25th days, respectively. The changes in proximate composition, total volatile base nitrogen, free fatty acid, peroxide value, thiobarbituric acid reactive substance, total viable count and sensory evaluation were analyzed. The onset of spoilage was delayed in seaweed treated samples. Tilapia got 6 days' shelf life extension, when treated with 1%–1.5% of seaweed extract as compared to the control sample. Novelty impact statement: The present study showed the potential of seaweed as a natural preservative in chilled stored fish. Seaweed is a good source of phenolic compounds that has potent antioxidant and antimicrobial properties, which is expected to be responsible for the preservative effect. [ABSTRACT FROM AUTHOR]

Background: Indiscriminate use of harmful synthetic preservatives to extend the shelf life of fish needs to be avoided. The objective of the present work was to study the qualitative and quantitative properties and bioactive properties of black tea powder found in local markets of Maharashtra. Methods: Low-value tea powder was selected through market survey and proximate analysis, total phenolic (Folin-Ciocalteau) and qualitative analysis (Agilent LC-MS system) for phenolic compounds including antioxidant properties was carried out using standard methods. Result: The results for proximate content were protein (21.15%), lipids (1.3%), total ash (9.91%), crude fibre (18.35%) and moisture (3.3%). While total phenolic content was 220.02 mg GAE/g dry tea powder. Total 12 different bioactive compounds were identified by HR-LCMS. The antioxidant properties were DPPH (88.84%), ABTS (74.94%), FRAP (1398.24 µ mol Trolox/gram dry tea powder) and metal chelating activity (25.13%). Based on the findings of this preliminary study it is opined that, black tea powder can act as a promising source of low-cost tea polyphenols for incorporation as antioxidant and antimicrobial agent for fish meat value addition. [ABSTRACT FROM AUTHOR]

Background: Tea polyphenols are extracted from top two-four young leaves and leaf buds of tea plant, while the bottom leaves of tea shrub are considered as an agricultural waste. Hence, an attempt has been made to utilise them as an alternate source of low-cost natural antioxidant. Methods: Green tea shrub bottom leaves of Camellia sinensis Var. assamica/TV-23 were procured from Estate-Seni Mora Bagan, Karanga kamar, Hazarika Gaon, Tal. Karga, Dist. Jorhat, Assam. Proximate analysis, total phenolic (Folin-Ciocalteau) and qualitative analysis (Agilent LC-MS system) for phenolic compounds including antioxidant properties was carried out using standard analytical methods. Result: The results for proximate content were protein (14.43%), lipids (4.44%), total ash (4.94%), crude fibre (33.63%) and moisture (3.20%). A total phenolic content of dry green tea powder extracts prepared by using ethanol was 105.68 mg GAE/g dry tea powder. Total 12 different bioactive compounds were identified by HR-LCMS. The antioxidant properties were DPPH (89.82%), ABTS (74.71%), FRAP (1053.92 µ mol Trolox/gram dry tea powder) and metal chelating activity (17.51%). Based on the study it is opined that; tea shrub bottom leaves can act as a promising source of low-cost tea polyphenols when extracted with ethanol as a solvent for value added fish product shelf life extension. [ABSTRACT FROM AUTHOR]