Study on lipophilic (C40) and hydrophilic (C50) carotenoids : production from shrimp waste and saffron as potential halal pigments

Abstract

A perceptible visual aesthetics in terms of colour is one of the important aspects for product marketability and acceptability. This is due to colour itself being inherently ubiquitous and capable of conveying valuable messages of the products. Nevertheless, various controversial issues regarding the safety of synthetic colourant have drawn a great deal of attention from consumers. Carotenoids are an excellent source of colouring agent that is acknowledged for its bioactive compounds ability and pro vitamin A and antioxidant activity. It is believed to aid in enhancing one’s health while also capable of creating a visually appealing image to consumers. Astaxanthin is a reddish lipophilic carotenoid (C40) has been reported to have greater antioxidant activities by ten-fold compared to other carotenoids, and 100 times better than α-tocopherol. In contrast, crocin is known as one of the unique hydrophilic carotenoid (C50) that produces yellowish red colour due to its water solubility properties. Thus, this research has aimed to explore lipophilic and hydrophilic carotenoids from natural resources as potential halal biocolourants, specifically from shrimp waste and saffron. Astaxanthin extraction from shrimp waste has been undertaken using different extraction methods, such as chemicals extraction, high pressure processing (HPP) and supercritical fluid extraction (SFE) technologies. These methods have yielded the highest amount of total astaxanthin content at 5701.99, 308.58, and 198.27 μg/g DW respectively. Although the total astaxanthin content produced by SFE was lower than via chemical and HPP extraction, it has produced high purity extracts enriched with astaxanthin. Furthermore, the application of such environmentally-friendly technology is a cost-effective and swift operation concomitantly. It is also capable of producing quality product without generating toxic substances, and causes minimal degradation only of the active compounds. Meanwhile, maceration extraction has been done to extract hydrophilic carotenoids in saffron from different localities (i.e. Iran, Turkey, Kashmir) as another potential halal biocolourant. The highest amount of crocin content has been detected in Iranian saffron at 11414.67 μg/g DW. Next, a screening assessment of the antioxidant, antibacterial, and antifungal in crocin and astaxanthin has also been performed. Their respective extracts have displayed strong activity on DPPH scavenging radicals, which is determined by IC50 values at 283.918 and 589.628 μg/ml respectively. Moreover, with regards of the antimicrobial assay performed, crocin has shown potential as an antimicrobial agent specifically against Staphylococcus epidermidis. Besides, colour stabilities of astaxanthin and crocin have also been evaluated across different period via salinity, pH, and UV and heat stability tests. Astaxanthin was observed to be unstable at the highest concentration of NaCl, whereas crocin is stable at different NaCl concentrations. They are both unstable towards acidic condition. Then, astaxanthin is more stable at a higher temperature and under UV irradiation compared to crocin. Finally, astaxanthin-PLA and crocin-PVA coatings stability have also been evaluated using salinity and pH stability test, with astaxanthin-PLA being stable when treated with different salinities and pH. However, the presence of NaCl and alkaline pH has decreased the crocin-PVA colour stability. Additionally, the presence of light has also been determined to be a major factor influencing the colour variations and stability of the coating.