Nutritional profile and in vitro immunomodulatory activity of protein extract from goat placenta and fermented extraction residual

Abstract The goat placenta has exhibited bioactive properties, but it is underutilized. In this study, the protein was extracted from goat placenta and the extraction residual were fermented by Bacillus subtilis . The placenta protein extract and fermented extraction residual were evaluated with their in vitro immunomodulatory activity (characterized by stimulation index [SI]) at different pH and temperature and nutritional profiles. For placenta protein extract, multiple factors were studied and the optimal conditions for maximal SI were obtained under a response surface methodology. The maximal stimulation index reached 132% for placenta protein extract. For fermented extraction residual, the SI reached 19% at 35 hr fermentation. For the stability of immunomodulatory activity, the optimal temperature and pH for protein extract were 30°C and 7. The fermented extraction residual showed higher temperature and pH stability than protein extract. For nutritional profiles, all essential amino acids were present in the placenta protein extract and fermented extraction residual. After extraction, protein extract showed higher amino acid scores than raw placenta. This study provided references for the utilization of goat placenta for producing valuable protein products for application in food and pharmaceutical industries. Practical applications China is abundant in goat placenta resources. The annual output of goat in China exceeds 200 million and more than 5 million goat placentas are available. The goat placenta containing more than 80% protein and many kinds of amino acids, possess high nutritional value. However, the lack of deep‐processing technology gives rise to most of the goat placenta being thrown away as garbage, so the utilization rate is less than 3%. It is of great practical significance to fully develop and utilize goat placenta and there will be wide marketing prospects. This study provided references for the utilization of goat placenta for producing valuable protein products for application in the food and pharmaceutical industries.