ABSTRACT
The utilization of synthetic dyes in food industries is a great concern for food safety and health issues. So, natural pigments can be an excellent substitute for synthetic dyes and also health-friendly for consumers. In the experiment, natural pigments were extracted from tomato (Solanum lycopersicum L.), turmeric (Curcuma longa L.) and red amaranth (Amaranthus tricolor L.). Then the stability and consumer acceptance of the extracted pigments were examined. The highest amount of pigment was extracted from turmeric (2.14 ± 0.30 %) with ethanol solvent, followed by tomato (0.67 ± 0.06 %) with hexane: acetone (1:1) solvent, and red amaranth (0.78 ± 0.05 %) with acetone solvent. Turmeric pigment showed the highest stability in high temperatures and light exposure. All of the pigments were highly stable in a neutral environment; however, tomato pigment showed the highest stability index (84.33 ± 2.52) at pH 3.0, but turmeric pigment showed the highest stability (91.67 ± 1.53) at pH 5.0. The simple preference test revealed that the use of turmeric pigment in boiled rice had the highest acceptance rate, and in terms of taste and flavor, red amaranth pigments in ice cream. So turmeric pigment can be utilized in high-temperature processing and/or acidic foods, but tomato and red amaranth pigments might be in low-temperature processing foods such as the ice-cream and soft drinks processing industry.
ABSTRACT
Among the diverse array of heat shock proteins across the three domains of life, mitochondria-targeted small heat shock proteins (sHSPs) are evolved in the plant lineage. However, they remained mysterious and understudied. In this study, we reported a systematic study of a novel mitochondria-targeted nuclear sHSP from eggplant (Solanum melongena L.; SmsHSP24.1). Differential expression of SmsHSP24.1 indicated its positive role exerted during stress conditions. Escherichia coli-BL21 cell line overexpressing the SmsHSP24.1 showed excellent thermo-tolerance ability, tolerating up to 52°C. Spectrometry and electron microscopy revealed a multimeric structure of the protein which acted as a molecular chaperone at high temperatures. Overexpression of SmsHSP24.1 significantly enhanced resistance against heat, drought, and salt stresses and showed rapid germination in constitutively overexpressed eggplant lines. RNA-seq analysis reveals an apparent upregulation of a set of reactive oxygen species (ROS) scavenging enzymes of the glutathione (GHS) pathway and mitochondrial electron transport chain (ETC). Significant upregulation was also observed in auxin biosynthesis and cell-wall remodeling transcripts in overexpressed lines. qPCR, biochemical and physiological analysis further aligned with the finding of transcriptome analysis and suggested an essential role of SmsHSP24.1 under various stress responses and positive physiological influence on the growth of eggplants. Therefore, this gene has immense potential in engineering stress-resilient crop plants.
