Optimization of Conditions for Biological Removal of Patulin from Apple Pomace Feed and Evaluation of Nutrients in the Feed Before and After Removal of Patulin

In order to reduce patulin content in apple pomace, a strain of Aspergillus miger FS10, which had the ability to degrade patulin, was used as fermentation strain to ferment patulin contaminated apple pomace for detoxification. The condition of inoculation quantity, material to water ratio, fermentation time and temperature were optimized by single-factor experiment and the analysis of response surface methodology determined the optimum fermentation conditions. Nutritional status was evaluated with the treatment of Aspergillus niger inoculation in apple pomace. The results indicated that the optimal treatment conditions in Aspergillus niger fermentative degradation were: Inoculation volume 10%, 31 ℃ for fermentation temperature, 4 d for fermentation time, and 1: 3.2 (g/mL) for the ratio of material to water. Patulin in apple pomace could be completely removed. The relative error between the verification result and the theoretical value was 1.67%, indicating that the optimized parameters were feasible and had practical application value. Evaluation of nutrients in apple pomace before and after fermentation indicated that the crude fiber content in apple pomace decreased from 20.26% to 17.32%, the crude protein content increased from 8.16% to 10.08%, the crude fat content increased from 3.32% to 4.06%, total amino acid content increased from 64.43 mg/g to 73.78 mg/g. In short, the research illustrated that the Aspergillus niger fermentation could not only remove patulin from contaminated apple pomace, but also effectively improve the nutritional value of apple pomace. These findings provided strong technical support for the development of safe and nutritious apple pomace feed.