Extraction, optimization, and functional quality evaluation of carotenoproteins from shrimp processing side streams through enzymatic process

The study aimed to develop an effective and eco-friendly enzymatic process to extract carotenoproteins from shrimp waste. The optimization of enzymatic hydrolysis conditions to maximize the degree of deproteinization (DDP) of carotenoprotein from shrimp head waste (SHW) and shrimp shell waste (SSW) was conducted separately using the Box-Behnken design of response surface methodology (RSM). To achieve a maximum DDP of 92.32% for SSW and 96.72% for SHW, the optimal hydrolysis conditions were determined as follows: temperature (SSW: 53.13 °C; SHW: 45.90 °C), pH (SSW: 7.13; SHW: 6.78), time (SSW: 90 min; SHW: 61.18 min), and enzyme/substrate ratio (SSW: 2 g/100 g; SHW: 1.18 g/100 g). The carotenoprotein effluent obtained was subjected to spray drying and subsequently assessed for color, nutritional, and functional characteristics. The carotenoprotein from shrimp shell (CpSS) contained a higher essential amino acid score than carotenoprotein from shrimp head (CpSH). CpSS had a higher whiteness index of 82.05, while CpSH had 64.04. Both CpSS and CpSH showed good functional properties viz solubility, emulsion, and foaming properties. The maximum solubility of CpSH and CpSS was determined to be 92.94% and 96.48% at pH 10.0, respectively. The highest emulsion capacity (CpSH: 81.33%, CpSS: 70.13%) and stability (CpSH: 57.06%, CpSS: 63.05%) were observed at 3% carotenoprotein concentration. Similarly, the highest values of foaming capacity (CpSH: 27.66%, CpSS: 105.5%) and stability (CpSH: 23.83%, CpSS: 105.33%) were also found at the same 3% carotenoprotein concentration. In conclusion, the carotenoproteins obtained from shrimp waste showed favorable attributes in terms of color, amino acid composition, and functional properties. These findings strongly suggest the potential applicability of CpSS and CpSH as valuable resources in various domains. CpSS, with its higher whiteness index, greater amino acid content, and superior functional characteristics, may find suitability as functional ingredients in human food products. Conversely, CpSH could be considered for incorporation into animal feed formulations.