Upgrading of Mixed Food Industry Side-Streams by Solid-State Fermentation with P. ostreatus

Abstract

In the frame of efforts to exploit agroindustrial side-streams and wastes (AISS) for added-value products that are based on single cell protein (SCP), mixed substrates consisting of brewer's spent grains (BSG), malt spent rootlets (MSR), cheese whey, molasses, orange, and potato pulps, were used for growth of the edible mushroom Pleurotus ostreatus. The substrates were mixed in various combinations, and were used for P. ostreatus growth at various conditions. The substrate, for which the highest sugar consumption, protein increase, and mycelium yield were observed, consisted of 20 mL molasses (4 • Baume density), 20 mL potato pulp, 5 mL whey, 5 mL orange pulp, 30 g BSG, and 5 g MSR (at 25 • C and substrate pH 4). The mycelium-enriched product was analyzed for protein, fat, minerals (Ca, Mg, Fe, Cu), and aroma volatile compounds, indicating the potential for use as nutritious supplement for food, feed, or microbiology uses. The product was also autolyzed, freeze-dried, powdered, and analyzed for total ribonucleic acid content, showing the potential for use as a commercial natural food flavor enhancer.

Refining Citrus Wastes: From Discarded Oranges to Efficient Brewing Biocatalyst, Aromatic Beer, and Alternative Yeast Extract Production

“…In previous studies, mixed substrates, consisting of AIWs such as brewers' spent grains, spent malt rootlets, cheese whey, molasses, orange, and potato pulps, were used for the production of single-cell protein, edible mushrooms, AYE, enriched livestock feeds, etc. [43][44][45]. In [43], a mycelium-enriched (Pleurotus ostreatus), mixed AIW product was evaluated as a potential raw material for AYE production for food, feed, or microbiology uses.…”

“…[43][44][45]. In [43], a mycelium-enriched (Pleurotus ostreatus), mixed AIW product was evaluated as a potential raw material for AYE production for food, feed, or microbiology uses. Specifically, the product was autolyzed, freeze-dried, powdered, and analyzed for total ribonucleic acid content, showing the potential for use as a commercial natural food flavor enhancer [43].…”

“…The significantly enhanced mineral content of AYE (Table 3), as well as other yeast or orange pulp nutrients present in CWBB, is the most possible explanation for this outcome. The mineral composition of molasses and orange pulp used in this study, as reported by [43], is also presented in Table 3. Further details on the composition of molasses and orange pulp can be found in other studies carried out in parallel with this study [43][44][45].…”

“…The mineral composition of molasses and orange pulp used in this study, as reported by [43], is also presented in Table 3. Further details on the composition of molasses and orange pulp can be found in other studies carried out in parallel with this study [43][44][45]. Different superscript letters in a column, regarding the type of yeast extract at the same concentration (CYE and AYE), indicate statistically significant differences among the strains (ANOVA, Tukey's HSD, p < 0.05).…”

A critical review on the biotechnological potential of Brewers’ waste: Challenges and future alternatives

“…SSF of BSG by Bacillus subtilis also results in an enhancement of amino acids, unsaturated fatty acids, and antioxidant content of BSG ( Tan et al, 2019 ). The edible fungus Pleurotus ostreatus was used to demonstrate protein enrichment of BSG ( Aggelopoulos et al, 2018 ). The authors identified BSG as a component that encourages the proliferation of fungal cells.…”