Preserving bioactive quality and color of novel frozen lemongrass puree tablets

Abstract

Fresh lemongrass samples pretreated using potassium metabisulfite solution (0.25% (w/v), hot water blanched for 2 min were frozen using static air (FSA) and continuous air (FCA) to prepare lemongrass puree tablets. The frozen product was packaged in polyethylene terephthalate (PET) jars and double‐layer zip pouches and stored at −2 and −18°C temperature for 6 months. The frozen product was analyzed for bioactive compounds and color characteristics after freezing and during storage at an interval of 2 months. Pretreatments exhibited a significant effect on all quality parameters except total flavonoid content and chroma (p < .05). All quality parameters except the ascorbic acid were significantly influenced by freezing method. Quality of frozen puree was influenced during storage with a significant impact of packaging material and storage period, regardless of storage temperature. Lemongrass puree samples frozen in static air, packaged in PET jars, and stored at −18°C showed highly acceptable quality after 6 months. Practical applications Fresh lemongrass has a limited shelf life after harvest. It is prone to browning, flavor loss, and weight loss due to high respiration rates. Freezing is a highly beneficial method of extending the shelf life of fresh produce without altering its fresh‐like quality. The present study demonstrates the effect of pre‐treatment, freezing, and storage on bioactive components and color characteristics of lemongrass puree with an aim to use it as an ingredient in ready‐to‐use form. These frozen tablets can be used directly while food preparation. This research would provide the progressive farmers and entrepreneurs with an innovative technology for food preservation that can be adapted to both on‐farm as well as industrial level. The present study can be utilized by food process engineers for defining the process for industrial production not only of this product also many new products. The investigations from this study show potential of lemongrass to be used as a natural food additive in food formulations, for enhanced flavor and health benefits.