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The need for the use of natural pigments in food manufacturing rises steadily. However, the application of natural pigments is limited by costly production and poor stability. Hence, the brown pigments from Camellia oleifera shells (disposal from tea oil production) were focused on in this study. The enzymatic extraction of Camellia oleifera fruit shell brown pigment (BP-CS) with ultrasound assistance was optimized by Box-Behnken design to cut extraction expenses. The yield of BP-CS was 38.56% under the optimized extraction parameters as extraction time of 77 min, extraction temperature of 64 °C, cellulose concentration of 10 mg/mL and liquid-solid ratio of 20mL/g. Subsequently, for promising no harmful ingredients in BP-CS, all 36 compounds were identified, and the primary constituents were flavonoids (quercitrin, quercetin) and organic acids (D-malic acid, citric acid). Via stability analysis, the brown pigment was pretty stable under heating, pH, and sunlight changes while was impacted by metal ions and redox agent conditions. Additionally, BP-CS was able to scavenge free radicals (DPPH, ABTS, · OH) and prevent the growth of microorganisms. Moreover, BP-CS could reduce α-amylase and tyrosinase activity, and both quenching mechanisms were static quenching. Overall, this work reveals that BP-CS is a valuable natural pigment, and is anticipated to be employed as a premium-quality pigment additive in the food industry. • Camellia oleifera fruit shells are an ideal source of brown plant pigments. • A novel process of the brown pigment by ultrasounic-assisted enzymolysis. • The chemical substance of the brown pigment was determined for the first time. • The brown pigment revealed good thermal, pH and photo stability. • The brown pigment with various bioactivities had a potential value of application.
Cheng et al. (Wed,) studied this question.