Solid State Fermentation as a Tool to Stabilize and Improve Nutritive Value of Fruit and Vegetable Discards: Effect on Nutritional Composition, In Vitro Ruminal Fermentation and Organic Matter Digestibility

Abstract

This research aimed to evaluate in vitro organic matter digestibility, fermentation characteristics and methane production of fruit and vegetable discards processed by solid state fermentation (SSF) by Rhizopus sp. Mixtures were composed of approximately 28% citric fruits, 35% other fruits and 37% vegetables. Fruit and vegetables were processed and fermented to obtain a stabilized product. Nutritional characterization and in vitro ruminal fermentation tests were performed to determine the effect of fungal bioconversion on digestibility, end products and gas production kinetics. Results indicate that SSF reduced organic matter and reducing sugars, while it increased crude protein and neutral detergent fiber, acid detergent fiber and neutral detergent insoluble protein. The in vitro gas production showed that SSF led to a reduction of the organic matter digestibility (p < 0.001), short chain fatty acids (SCFA; p = 0.003) and CH4 (p = 0.002). SSF reduced the gas production from the insoluble fraction (p = 0.001), without modifying the production rate (p = 0.676) or the lag time (p = 0.574). Regarding SCFA profile, SSF increased acetic (p = 0.020) and decreased propionic (p = 0.004) and butyric (p = 0.006) acids proportions, increasing acetic to propionic (p = 0.008) and acetic plus butyric to propionic (p = 0.011) ratios. SSF succeeded in obtaining a stabilized material enriched in protein, but at the expense of a reduction of protein availability and organic matter digestibility. These changes should be considered before including them in a ruminant’s rations.

Improved Nutritional Value of Surplus Bread and Perennial Ryegrass Extracts Via Solid-State Fermentation (SSF) with Rhizopus oligosporus

“…The main driver for the mass change in all macronutrients was the digestion of starch as the primary carbon source of the substrate. These changes have also been described in the literature, as fermentation with Rmo transforms carbohydrates into fungal biomass, thereby increasing the concentration of crude protein and crude bre 34 .…”

Biodegradation of Leguminous Husks into High Protein Feed Products Using Oyster Mushrooms (Pleurotus ostreatus)

“…The inevitable organic matter losses during biological treatments imply that an increased organic matter (OM) digestibility is needed to compensate for the losses. Hence, solid-state fermentation (SSF) for 6-8 days has been recommended as the maximum time of fermentation to reduce dry matter loss 20 . However, Asmare 16 recommended an optimum fermentation period of six weeks for the biodegradation of any substrate.…”

Upgrading agrifood co-products via solid fermentation yields environmental benefits under specific conditions only

“…SSF is based on the colonization of a solid substrate by a biological agent which, in the case of feed applications, allows to enhance or even unlock the nutritional value of brous feedstocks, mainly through lignocellulose degradation, proteins concentration and digestibility enhancement [6][7][8][9] . Applied to…”

“…Among these solutions, "waste-to-nutrition" pathways, transforming organic wastes, residues and coproducts into edible ingredients, are increasingly promoted 5 . In this study, we assess the conditions under which fungal solid substrate fermentation (SSF) can sustainably be used as an alternative valorization option for agrifood co-products.SSF is based on the colonization of a solid substrate by a biological agent which, in the case of feed applications, allows to enhance or even unlock the nutritional value of brous feedstocks, mainly through lignocellulose degradation, proteins concentration and digestibility enhancement [6][7][8][9] . Applied to…”