Penicillium sp. Cis16 improves soluble dietary fiber content in citrus dregs fermentation

ABSTRACT Producing dietary fiber products containing soluble dietary fiber (SDF) content higher than 30% that is both physiologically beneficial and nutritionally balanced is challenging. A filamentous fungus from moldy citrus fruit was previously isolated and identified as Penicillium sp. Cis16 whose fermentation broth confirmed to have no acute toxicity in this study. Initial experiments showed that the isolate yielded higher SDF and total dietary fiber (TDF) than that of Trichoderma viride (P < .01), a fungus commonly used to decompose plant fiber, indicating that the strain can be used to ferment citrus dregs producing SDF. Optimal fermentation conditions for the isolate were determined and comprised of solid seed amplification mode, 2:1 ratio of peels to pomace, fermentation temperature of 28°C, and fermentation time of 3 days. The SDF yields improved from 6.77% to 36.56%. These results demonstrated that Penicillium sp. Cis16 fermentation was good to produce balanced dietary fiber containing higher SDF levels.