Production of microbial pigments from whey and their applications: a review

Purpose Whey is a by-product of paneer, cheese and casein industry and considered as a dairy waste. Worldwide, approximately 180-1,900 million tons of whey is produced annually. Whey is classified as a high pollutant due to its organic matter level. Owing to its high chemical oxygen demand and biological oxygen demand, it is a big threat to the environment. Whey contains 4.5%-5.0% lactose, 0.6%-0.7% protein, 0.4%-0.5% lipids, vitamins and minerals. Due to its high nutritional profile, it is a good substrate for the microorganisms for production of natural pigments. The purpose of this paper is to review the utilization of low cost substrate (whey) for production of various types of pigments and their applications in different sectors. Design/methodology/approach The databases for the search included: Scopus, PubMed, Science Direct, Web of Science, Research gate and Google. The main search was directed towards different types of natural pigments, stability, technologies for enhancing their production and contribution towards circular economy. Approximately 100 research papers were initially screened. A global search was conducted about natural pigments. Research articles, review papers, books, articles in press and book chapters were the type of search for writing this review paper. Findings Production of natural pigments using whey and their addition in food products not only improves the colour of food but also enhances the antioxidant properties of food products, helping the health benefits by chelating free radicals from the body. The sustainable use of whey for production of natural pigments can improve the bio-based economy of different industries and thereof the national economy. Originality/value Efficient utilization of whey can bring a lot more opportunities for production of natural pigments in a sustainable manner. The sustainable approach and circular economy concepts will benefit the dependent industries and health conscious consumers. The potential uses of whey for the production of natural pigments using diverse organisms are highlighted in this paper.