Processo Tecnológico: fabricação de queijo e um novo produto micoproteico funcional para harmonizar alimentos

Abstract

The Auricularia genus has stood out for synthesizing important bioactive compounds such as coagulating proteases for use in cheese production. The objective of this research was to evaluate two species of Auricularia for their milk coagulating activity and the potential of mycelial biomass as an ingredient for food product harmonization. The species Auricularia delicata DPUA 1625 and A. fuscosuccinea DPUA 1624 from the DPUA Culture Collection of the Federal University of Amazonas were cultivated on potato dextrose agar (PDA) supplemented with yeast extract (YE) at 28°C for 12 days. To evaluate in vitro mycelial growth (VCR) and mycelial density, the two species were cultivated in four media with 0.5% (w/v) YE: (1) Sabouraud agar (SAB+YE), (2) Malt Extract Agar (MEA+YE), (3) Glucose and Meat Peptone Agar (GYP), and (4) Malt, Glucose, and Meat Peptone Agar (MGYP). The same media used for liquid culture were then used for submerged fermentation. Ten mycelial discs were inoculated, and the bioprocess was conducted at 28 °C for 8 days at 150 rpm. The crude extracts obtained were evaluated for proteolytic activity using a 1% (w/v) azocasein solution as substrate and for milk coagulation activity using 10% (w/v) skim milk as substrate. Subsequently, the biological parameters were standardized: age and size of the inoculum, fermentation time, and carbon and nitrogen sources. The coagulant obtained from the standardization process was biochemically characterized for optimal pH and temperature, stability, ions, and inhibitors. For the production of cheese and flour-type food bioproducts, scaling was performed for industriallevel production. The flour was produced from dehydrated biomass, with the particle size determined, and the technological properties of the flour were analyzed: water absorption index (g/g), oil absorption capacity (%), and swelling capacity (g/g). Centesimal and microbiological analyses of the bioproducts were performed. Under the conditions evaluated, GYP agar favored mycelial growth and vigor and was selected as the medium for obtaining A. fuscosuccinea inoculum. In submerged fermentation, the liquid medium that favored protease synthesis for A. fuscosuccinea was MGYP (18.13 U/mL). In coagulation activity, A. fuscosuccinea synthesized coagulating proteases in 100% of the media, in which significant activity was observed in SAB+YE. The ideal conditions for the production of coagulating proteases with biochemical characteristics suitable for the dairy industry were: inoculum with eight days of cultivation, inoculum size 10%, during eight days of fermentation. The coagulant showed significant catalytic activity at pH 5.0 at 45°C, with stability at 55°C, and the enzymes were classified as aspartic proteases. The milk coagulating proteases of A. fuscosuccinea were efficient for the production of Minas frescal cheese, which had 56% moisture, 20.0% lipids, and 17.66% protein. The flour stood out as a by-product because it had a high content of 06.70% protein, 01.92% fiber, and 02% ash. For Auricularia delicata DPUA 1625, on GYP agar (glucose, peptone, and yeast extract agar), a significant mycelial growth rate (9.73 mm/day) and highly dense mycelial vigor were observed. The GYP medium (71.60 U/mL) favored protease synthesis. During the eight-day cultivation period, significant proteolytic activity (78.60 U/mL) was determined. The proteases showed significant catalytic activity at pH 5.0, at 50 °C, maintained stability in the pH range of 5.0 to 7.0 up to 50 °C, and were classified as serine and aspartic proteases. The exploitation of Amazonian mushrooms, such as Auricularia spp., broadens the prospects for the sustainable use of Amazonian biodiversity, promoting innovation in fermentation processes and the introduction of new biotechnological routes in the industrial sector.