Food services in times of uncertainty: Remodeling operations, changing trends, and looking into perspectives after the COVID-19 pandemic.

BACKGROUND: Social distancing and the economic downturn imposed by COVID-19 have significantly affected the food service segment. Therefore, operation recovery and adapting to a new reality must be achieved as quickly and efficiently as possible. Studies on this topic, which have been conceptualized in various parts of the world, have brought new ideas to light to mitigate the negative effects of COVID-19 on food service. SCOPE AND APPROACH: This study aimed to discuss the impact of COVID-19 on food service operations, changes in pre-existing trends, and post-pandemic perspectives. KEY FINDINGS AND CONCLUSIONS: COVID-19 has changed all business segments. When dining rooms were forced to close, many food services had to resort to innovation to survive, and many added deliveries and/or adopted the dark kitchen models in one of their many forms. It is expected that the demand for delivery, dark kitchens, and the adoption of technological solutions, for example, contactless payment, will remain in the post-pandemic scenario. Food quality control measures have become more strictly enforced, not only to prevent SARS-CoV-2 contamination but also to increase credibility with the customer. These long-established food safety practices have returned to the spotlight, been revised, and should be maintained for well into the post-pandemic period. Restaurants are operating again and restrictions on opening hours and capacity have been relaxed or eliminated. Continued studies on this topic are important for supporting creative and scientifically based solutions for socio-economic recovery.

Production of Enzymes from Agroindustrial Wastes by Biosurfactant-Producing Strains of Bacillus subtilis.

Bacteria in the genus Bacillus are the source of several enzymes of current industrial interest. Hydrolases, such as amylases, proteases, and lipases, are the main enzymes consumed worldwide and have applications in a wide range of products and industrial processes. Fermentation processes by Bacillus subtilis using cassava wastewater as a substrate are reported in the technical literature; however, the same combination of microorganisms and this culture medium is limited or nonexistent. In this paper, the amylase, protease, and lipase production of ten Bacillus subtilis strains previously identified as biosurfactant producers in cassava wastewater was evaluated. The LB1a and LB5a strains were selected for analysis using a synthetic medium and cassava wastewater and were identified as good enzyme producers, especially of amylases and proteases. In addition, the enzymatic activity results indicate that cassava wastewater was better than the synthetic medium for the induction of these enzymes.

Response surface analysis for the production of an enantioselective lipase from Aspergillus niger by solid-state fermentation.

The lipase produced by the Aspergillus niger strain AC-54 has been widely studied due to its enantioselectivity for racemic mixtures. This study aimed to optimize the production of this enzyme using statistical methodology. Initially a Plackett-Burman (PB) design was used to evaluate the effects of the culture medium components and the culture conditions. Twelve factors were screened: water content, glucose, yeast extract, peptone, olive oil, temperature, NaH(2)P0(4), KH(2)P0(4), MgS0(4)-7H(2)0, CaCl(2), NaCI, and MnS0(4). The screening showed that the significant factors were water content, glucose, yeast extract, peptone, NaH(2)P0(4), and KH(2)P0(4), which were optimized using response surface methodology (RSM) and a mathematical model obtained to explain the behavioral process. The best lipase activity was attained using the following conditions: water content (20%), glucose (4.8%), yeast extract (4.0%), and NaH2P04 (4.0%). The predicted lipase activity was 33.03 U/ml and the experimental data confirmed the validity of the model. The enzymatic activity was expressed as micromoles of oleic acid released per minute of reaction (micromol/min).

Production of biosurfactant by Bacillus subtilis LB5a on a pilot scale using cassava wastewater as substrate.

The main characteristic of biosurfactants is their property of reducing the superficial and interfacial tension between two immiscible liquids of different polarities. The main obstacle to the application of biosurfactants is the high production costs, the use of alternative substrates being indicated to solve this problem. This work report the production of biosurfactant by Bacillus subtilis LB5a on a pilot scale using cassava wastewater as the substrate, and the study of the parameters related to its production. The cassava wastewater was heated, centrifuged and poured into a 40-liter batch pilot bioreactor adapted for simultaneous foam collection during the fermentative process. The temperature was maintained at 35 degrees C, agitation at 150 rpm and aeration 0.38 vvm during the first 12 h, and 0.63 vvm for the rest of the process. Samples of liquid fermentate were collected at regular intervals for the analysis of total carbohydrates, reducing sugars, pH, CFU/mL count and superficial tension. The foam was centrifuged and the biosurfactant purified. The kinetic data of the process showed that both the microbial population, which reached a maximum after about 24 h, and the foam production of 10.6 L, peaked between 24 and 36 h, coinciding with the greatest production of biosurfactant. The yield of semi-purified surfactant in the foam was 2.4 g/L. The superficial tension of the medium was reduced from 51 to 27 mN/m and the critical micellar concentration was 11 mg/L, which, in principle, characterizes it as a good tensoactive agent. As a function of its composition and productivity, cassava wastewater was identified as a good substrate for the production of the biosurfactant.

Optimization of R-(+)-alpha-terpineol production by the biotransformation of R-(+)-limonene.

R-(+)-limonene is an abundant and non-expensive by-product of the citrus industry and is, therefore, a suitable starting material for the production of natural flavor and fragrance compounds. The biotransformation of R-(+)-limonene to R-(+)-alpha-terpineol by Fusarium oxysporum 152b has already been reported, although the influence of the main process parameters on the production has not yet been evaluated. In this paper, a Plackett-Burman screening design was used to define the effects of the medium composition (glucose, peptone, yeast extract, malt extract and pH), the presence of a co-substrate (biosurfactant), the cultivation conditions (temperature, agitation), the substrate concentration and the inoculum/culture medium ratio on the absolute amount of R-(+)-alpha-terpineol resulting from this biotransformation. The process conditions were further optimized applying response surface methodology (RSM). The volatiles were extracted using a SPME device and were subsequently quantified by GC-FID and identified by GC-MS. The best results were obtained using 0.5% (v/m) R-(+)-limonene in pure distilled water as the culture medium with an inoculum/culture medium ratio of 0.25 (m/m) and 72 h cultivation at 26 degrees C/240 rpm. Under these conditions the concentration of R-(+)-alpha-terpineol in the culture medium reached 2.4 g L(-1), a production almost six times greater than in earlier trials. The presence of a biosurfactant (0-500 mg L(-1)) did not significantly increase the yield.