Losses in flavour of Indian potatoes: Influence of storage temperature

Abstract

Fresh potatoes are preferred for cooking over stored potatoes due to the superior taste of freshly harvested potatoes since with the increase in storage duration, quality as well as taste of potatoes are known to deteriorate. Therefore, the aim of the present study was to investigate the effect of storage (for 180 days at 4 °C and 12 °C) on concentration of flavouring compounds, particularly umami 5’ nucleotides viz. adenosine monophosphate (AMP) and guanosine monophosphate (GMP) along with changes in carbohydrates. AMP+GMP content ranged from 2.19 to 4.69 μg/g FW (fresh weight) in freshly harvested raw and microwaved tubers of 11 potato cultivars. The content of umami 5’ nucleotides increased to appreciable amounts during microwave cooking (3.52 to 8.92 μg/g FW). During storage at 4 and 12 °C, flavouring compounds ranged from 0.29 to 2.39 μg/g FW and 0.34 to 2.92 μg/g FW in raw tubers and from 0.91 to 5.64 μg/gFW and 2.00 to 4.28 μg/gFW in microwaved potatoes, respectively. On an average, there was 19% and 10% decrease in starch content whereas 112% and 69% increase in reducing sugars and 90% and 57% increase in sucrose content, at 4 °C and 12 °C storage, respectively. It is known that the quality and taste of potatoes deteriorates during storage due to starch hydrolysis leading to reducing sugar accumulation, but this study has revealed that it is not only the sugar accumulation but also the decrease in flavouring compounds viz. AMP+GMP which results in poor taste of stored potatoes. Hence, sugars accumulation and deterioration of flavouring compounds together leads to poor taste of stored potatoes.