Anthocyanins are a group of water‐soluble polyphenolic pigments found primarily in flowers, vegetables, and fruits. These pigments play critical roles in plant and human health. Spectrophotometric methods are a simple and inexpensive way to quantify anthocyanins in plant tissues. Two main spectrophotometric methods have been developed, organic solvent‐based, and pH differential methods. Both of these methods are subject to interference from light‐absorbing impurities and need to be optimized for different matrixes of different plant materials. Eight methods have been tested in this experiment to quantify anthocyanins in strawberry fruits. Six organic solvent‐based methods tested methanol, chloroform‐methanol, and MgO in different ratios. The other two methods were pH differential method and a combination of organic solvent‐based and pH differential method. Two methods used organic solvents (methanol and chloroform‐methanol) were the best in extracting anthocyanin from strawberry fruits. Adding MgO increased the pH of the extract and was less efficient in anthocyanin extraction. All other methods had lower anthocyanin yield compared with methanol and chloroform‐methanol methods and are not recommended for strawberry fruit anthocyanin extraction.

We determined the phenolic content and anti‐oxidation properties of ginger at different harvesting time and tested its effects on lipid droplet formation and glucose uptake in HepG2 cells. Ginger samples at different stages of maturity were harvested every two weeks starting from mid‐October for 16 weeks. Our data indicate that ginger has the highest phenolic contents and superior anti‐oxidation activity when harvested early (immature baby ginger); however, the concentration of phenolic contents and its anti‐oxidation activity were progressively reduced up to 50% as ginger matures. Furthermore, the data indicate that baby ginger extract inhibits lipid accumulation and triglyceride content in oleic acid‐induced HepG2 cells up to 20% in a dose‐dependent manner. Baby ginger exhibited significant inhibition of α‐amylase enzyme activity by 29.5% and ameliorated glucose uptake in HepG2 cell at similar level. Our results suggest that harvesting ginger at an appropriate (early) time may be beneficial for optimizing its biological active contents and qualitative properties. The data also suggest that a regular use of ginger can potentially lower incidences of obesity and diabetes.

Anthocyanins are a group of pigments with antioxidant activities that are present naturally in plants. The role of the pigment in human health and its quantitative analysis has attracted a lot of attention globally. A well-known and accurate method of anthocyanin quantification is based on spectrophotometric methods. However, these methods are subject to interference from impurities and need to be optimized for different plant matrixes and extraction conditions. Two experiments were designed to study (1) the effect of plant preparation methods (eg, fresh, frozen, and freeze-dried puree) on anthocyanin yield and (2) the effect of five anthocyanin extraction methods on anthocyanin yield of freeze-dried strawberry puree. Sample preparation methods did not have any effect on anthocyanin yield. Freeze-dried samples were used for their stability (ease of use and flexibility) to compare extraction methods. The anthocyanin yield was affected by the extraction method. Two methods containing chloroform gave the highest anthocyanin yield. One method with methanol:water:HCl gave intermediate results, and the pH differential and the other method with methanol:water:HCl (80:20:1) gave the lowest anthocyanin yields. Processing time (incubation time) was lowest in the pH differential method; however, the haze produced in this method may interfere with the spectrophotometric assessment of anthocyanins.