Determination of antioxidant/capacity in the dietary, food, drugs, and biological samples is an interesting approach for testing the safety of these compounds and for drug development. Investigating the google searching engines for the words (measurement + antioxidant + capacity) yielded more than 20 million results, which makes it very difficult to follow. Therefore, collecting the common methods to measure the antioxidant activity/capacity in the food products and biological samples will reduce the burden for both the students and researchers. Nowadays, it is widely accepted that a plant-based diet with a high intake of dietary sources such as vegetables, fruits, and other nutrient-rich plant foods may decrease the effect of oxidative stress-related diseases. In this review article, we have provided the most recent advances in the most common in vitro methods used for evaluating the antioxidant potential of numerous food products, plant extracts, and biological fluids. We have also provided detailed procedures on how to perform them and analyze the results. This review article shall be a comprehensive reference for all techniques used in this area.

Purpose Watermelon (Citrullus lanatus) fruit and its rind are known to contain phytochemicals that may have health benefits. The aim of this paper is to investigate the potential hypocholesterolemic effect of watermelon fruit rind (WR) using rats who are fed a high-cholesterol diet. Design/methodology/approach Rats were divided into six groups and fed diets for eight weeks containing normal control diet or normal control diet with either 1% cholesterol, 5% WR, 10% WR, 1% cholesterol + 5% WR or 1% cholesterol + 10% WR. Triglycerides, total cholesterol and lipoprotein levels in serum and liver samples were determined, and histopathological examination of liver tissues was carried out. Findings Diets containing 1% cholesterol led to hypercholesterolemia, characterized by increased levels of total cholesterol and low-density lipoproteins in rat serum and liver samples. Incorporation of 10% WR into the diet of the otherwise hypercholesterolemic rats led to significant reduction in serum levels of total cholesterol (from 266.2 to 222.7 mg/dL) and low-density lipoproteins (from 159.5 to 94.4 mg/dL). In addition, these rats also exhibited improvements in hepatic tissue structure compared to the hypercholesterolemic rats. Originality/value These results support the potential use of WR as a hypocholesterolemic agent. Further research is needed to ascertain the hypocholesterolemic effect of WR in human.

The aim of this study was to fortify date palm spathes beverage with pollen grains. The nutritional quality and sensory attributes of the developed products were evaluated. The results showed that pollen grains significantly (P < 0.05) influenced the nutritional and sensory qualities of date palm spathe beverages. With minor exceptions, fortification of spathe beverage with pollen grains significantly (P < 0.05) increased the levels of protein, carbohydrate, fat, total dissolved solid (TDS), magnesium (Mg), iron (Fe), selenium (Se) and vitamins A, E, and C as well as the antioxidant activity (DPPH and FRAP) especially with 5% pollen grains. However, fortification reduced the levels of turbidity, boron (B), nickel (Ni), copper (Cu), zinc (Zn), and molybdenum (Mo). In terms of the colour, taste, and texture of the beverages, the panellists has no preference between the control beverage and 5% pollen grains. The highest overall acceptance was found for the control beverages without pollen grains, followed by those with 5% pollen grains. Overall, the inclusion of pollen grains in the formulation of date palm spathe beverage could enhance the nutritional quality without substantially influencing the sensory acceptability of the beverages.

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PurposeThe purpose of this study is to investigate the effect of roselle flower extract and date palm pollen on the nutritional and sensory qualities of date palm spathe beverage (DPSB).Design/methodology/approachThe nutritional composition and sensorial quality of the date palm spathe-based beverage were evaluated. The product was fortified with different concentrations (1 per cent and 5 per cent) of roselle flowers and 1 per cent date palm pollen grains.FindingsGenerally, fortification of the DPSB with roselle flowers only or the combination of roselle flowers and date palm pollen grains significantly affected the nutritional and sensory properties of the products. The total dissolved solids, turbidity and total contents of proteins; fats; carbohydrates; vitamins A, E and C; iron; nickel and copper were highest in the DPSB fortified with a mixture of 1 per cent roselle flower extract and 1 per cent pollen grains and lowest in the DPSB supplemented with 1 per cent roselle flower extract. The manganese and selenium contents were both highest and lowest in DPSB supplemented with 5 per cent and 1 per cent roselle flower extract, respectively. Antioxidant activity was highest in DPSB supplemented with the 5 per cent roselle flower extract and lowest in unfortified DPSB. Boron, molybdenum and zinc contents were highest in unfortified DPSB. All sensory attributes were highest in both the unfortified DPSB and that fortified with 1 per cent roselle flower extract.Originality/valueWhile fortification with a combination of 1 per cent roselle flower extract and 1 per cent date palm pollen grains improved the nutritional quality of the DPSB, it negatively affected the sensory attributes of the products.