Sustainable Production of Novel Oleogels Valorizing Microbial Oil Rich in Carotenoids Derived from Spent Coffee Grounds

Abstract

Sustainable food systems that employ renewable resources without competition with the food chain are drivers for the bioeconomy era. This study reports the valorization of microwave-pretreated spent coffee grounds (SCGs) to produce oleogels rich in bioactive compounds. Microbial oil rich in carotenoids (MOC) was produced under batch fermentation of Rhodosporidium toruloides using SCG enzymatic hydrolysates. Candelilla wax (CLW) could structure MOC and sunflower oil at a 3.3-fold lower concentration than that of carnauba wax (CBW). MOC-based oleogels with 10% CBW and 3% CLW showed an elastic-dominant and gel-like structure (tan δ ≪ 1), providing gelation and oil binding capacity (>95%). Dendritic structures of CBW-based oleogels and evenly distributed rod-like crystals of CLW-based ones were observed via polarized light microscopy. MOC-based oleogels exhibited similar Fourier-transform infrared spectroscopy spectra. X-ray diffractograms of oleogels were distinguished by the oil type that presented β′-type polymorphism. MOC-based oleogels could be applied in confectionary products and spreads as substitutes for trans fatty acids, reformulating fat-containing food products.

Microbial Melanin: Renewable Feedstock and Emerging Applications in Food-Related Systems

“…Numerous agro-residues-fruit and vegetable waste, whey, molasses, corn steep liquor, and wheat bran-have been evaluated as potential nutrient sources to produce pigments of microbial origin [11,12]. The bioconversion of waste streams into added-value products such as pigments [13], biopolymers [14], organic acids [15,16], and microbial oil [17,18] comply with the circular bioeconomy era. Microbial biotechnology is the most important tool for the development of closed-loop circular bioprocesses that could stepwise re-introduce waste into the value-added food chain as novel products [19].…”

Bioconversion of Agro-Residues into Microbial Oil-Based Oleochemicals Employing Packed Bed Bioreactor

“…Several bioprocesses, including submerged fermentation and solid-state fermentation (SSF), have been employed to produce value-added products valorizing agro-industrial residues. Amongst the most promising biometabolites are biopolymers, organic acids, enzymes, microbial oil and carotenoids [1], polyols, biopesticides, and biosurfactants [1][2][3][4][5][6][7][8][9][10][11]. The alternative of SSF could overcome obstacles such as catabolite repression and substrate inhibition, while low requirements of energy, wastewater output and production cost, render SSF a very attractive bioprocess for the production of microbial metabolites.…”

“…The palm tree generates around 90% of waste biomass, including PKC and palm-pressed fiber (PPF) besides others, while only 10% corresponds to oil production [15]. Oil palm constitutes a significant contributor to the deforestation of tropical areas, with soybeans, maize, oil palm, rice, and sugar cane creating almost 50% of the 69 Mha deforestation associated with cropland expansion [1]. The worldwide production of PKC and CoSC reached 10.44 million t and 15.12 million t in 2021/2022, respectively [16].…”