Durian (Durio zibethinus Murr.), like many other exotic, tropical, and conventional fruits, is important in the prevention of different diseases. In this study, the characterization of the main bioactive compounds of the most popular cultivars of durian and their properties are described. The changes in the quality indices of the antioxidant status were determined by CUPRAC, ABTS, FRAP, DPPH, and ORAC assays. The profiling of phytochemicals was carried out by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). For the first time, in vitro studies were performed by the interaction of extracted durian polyphenols with human serum proteins (HSP) such as human serum albumin (HSAlb), fibrinogen (HSFib) and globulin (HSGlo) as novel biomarkers of coronary artery disease (CAD). The fluorescence measurements of the resulting intensity and calculated binding properties of the interaction of polyphenols with proteins showed that the most reactive was Monthong durian cultivar. This study suggests that durian cultivars have relatively strong antioxidant, binding, and health potentials and could be a significant source of natural antioxidants used in daily fresh consumption and for functional foods.

The in vitro scavenging ability of roselle anthocyanin extract (RAE) against reactive nitrogen species (RNS) was compared to anthocyanin extracted from black carrots and red grapes. These anthocyanin samples exhibited concentration and pH dependence on nitrite scavenging activity, with the activity decreasing as pH was increased over the range of 3.0 to 9.0. Concentration dependent activity was also observed for the nitric oxide scavenging and inhibition of peroxynitrite induced oxidation of Evans blue dyes. The potency of RNS scavenging activity for the anthocyanins tested was in the order of grapes > roselle > black carrots. The RAE was then evaluated for its capacity in nitrite reduction in Vienna pork sausage and traditional Thai fermented pork, called Nham. The residual nitrite in Vienna pork sausage treated with 0.3 % RAE at 125 or 250 mg/kg reduced nitrite to 65 and 168 mg/kg respectively, after being stored at 4±1 ๐C for 24 days. The residual nitrite in all Nham samples rapidly decreased around 90 % of the initial nitrite level after 3 days of fermentation at 30±1 ๐C. Overall results show that RAE was a good source of strong reactive nitrogen species scavengers and can potentially be used as a natural nitrite reduction agent in meat products.

Mango seed kernel extract (MSKE) has been reported to contain high content of phenolic compounds, and exhibit strong in vitro antioxidant activity. This study aimed to evaluate the application of MSKE as natural antioxidant in frozen minced fish products. The effect of MSKE at different concentrations (0%, 1%, 2% and 3% w/w) on retarding lipid and protein oxidation in minced fish samples during frozen storage at -18 ºC was investigated and compared to the chemical antioxidant, BHT (butylated hydroxytoluene) at 0.01% w/w. Physicochemical parameters related to the oxidative stability of minced fish samples including pH, color, peroxide value (PV), thiobarbituric acid reactive substances (TBARS), conjugated diene (CD), protein carbonyl, sulfphydryl groups (SH), and total volatile base nitrogen (TVB-N) were determined. The results showed that the pH values had significantly increased in all samples being treated with MSKE and BHT after 12 weeks of frozen storage. Samples treated with 3% MSKE or BHT were significantly lower in lightness (L*) and redness (a*) but presented no significant effects on yellowness (b*). Moreover, MSKE at all concentrations studied, and BHT, significantly delayed the increase in values of PV, TBARS, CD, protein carbonyl, and TVB-N and the decrease in values of SH compared to the control sample. At the end of storage, no significant odd odor and flavor assessed by sensory test were detected in frozen minced fish. In conclusion, MSKE at 3% w/w proved to be as efficient as BHT in retarding lipid and protein oxidation in minced fish during frozen storage.

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