Cyclodextrin glycosyltransferase (CGTase) is an enzyme that produces cyclodextrins (CDs) from starch and related carbohydrates, producing a mixture of α-, β-, and γ-CDs in different amounts. CGTase production, mainly by Bacillus sp., depends on fermentation conditions such as pH, temperature, concentration of nutrients, carbon and nitrogen sources, among others. Bacillus megaterium CGTase produces those three types of CDs, however, β-CD should prevail. Although waxy corn starch (CS) is used industrially to obtain CGTase and CDs because of its high amylopectin content, alternative sources such as amaranth starch (AS) could be used to accomplish those purposes. AS has high susceptibility to the amylolytic activity of CGTase because of its 80% amylopectin content. Therefore, the aim of this work was evaluate the AS as carbon source for CGTase production by B. megaterium in a submerged fermentation. Afterwards, the CGTase was purified partially and its activity to synthesize α-, β- and γ-CDs was evaluated using 1% AS as substrate. B. megaterium produced a 66 kDa CGTase (Topt=50°C; pHopt=8.0), from the early exponential growth phase which lasted 36 h. The maximum CGTase specific activity (106.62±8.33 U/mg protein) was obtained after 36 h of culture. CGTase obtained with a Km=0.152 mM and a Vmax=13.4 µM/min yielded 40.47% total CDs using AS which was roughly twice as much as that of corn starch (CS; 24.48%). High costs to produce CDs in the pharmaceutical and food industries might be reduced by using AS because of its higher α-, β- and γ-CDs production (12.81%, 17.94% and 9.92%, respectively) in a shorter time than that needed for CS.

The influence of the temperature-dependent viscosity on the electroosmotic flow through a porous medium in a microchannel of parallel flat plates. At the end, an imposed electric field induces Joule heating and temperature gradients, modifying the viscosity of the fluid. The Phan-Thien–Tanner and Darcy–Forchheimer models describe the viscoelastic fluid through the porous media. Consequently, the electric double layer (EDL) overlaps at the center plane of the microchannel, causing an electrically charged porous matrix and modifying the zeta potential along the microchannel walls. Therefore, we define a zeta potential ratio of the porous matrix and that at the microchannel walls. Unlike similar investigations, the boundary condition for the zeta potential varies locally due to the temperature field, modifying the interaction among hydrodynamics, electrical, viscoelastic, thermal and porosity effects. A modified Péclet number is defined as a function of the porosity and thermal conductivity of the fluid and an effective charge density is determined based on the Poisson–Boltzmann equation, accounting for the pore size and the zeta potential ratio. The set of equations are solved numerically considering the lubrication approximation theory. We found that the influence of the temperature-dependent viscosity increases the shear stresses at the EDL region, particularly where the temperature rises to maximum values. Also, the overlapping of the EDL occurs mainly for low values of permeability. Finally, the pressure gradient involved in the Darcy law can be altered through the zeta potential ratio.

Power generation using renewable technologies has become a primordial option to satisfy the energy demand all over the world, with solar concentrating technologies widely applied for this purpose. A combination of a parabolic trough collector with direct steam generation has been considered an excellent option for power generation as the economic cost and complexity in the plant are reduced. The thermal evaluation of a solar power plant as well as the PTC in the DSG process is very important in viability and economic analyses. In this sense, as the main objective of this work, a numerical tool for evaluating DSG with PTC technology was developed. The SOLEEC software is a versatile, reliable, accurate, and user-friendly option to thermally evaluate a DSG with PTC technology. The user has the possibility of comparing the thermal behavior of different geometrical dimensions for a PTC and even consider different materials to satisfy the demand of superheated steam by a DSG process. The software has an error of less than 5% when compared with the literature results and was used in this paper to evaluate a power plant in Mexico, showing that the change to DSG proposing different PTC could reduce the solar field by about 35%.

Objective: This work evaluates the effect of a dietary supply of amaranth, oats and lentils as a protein source on anthropometric measurements, the chemical composition in meat, as well as antioxidant activity in meat peptides and secretion of the snail (Helix aspersa Múller). Design/methodology/approach: We worked with three groups of snails of 36 individuals and a control group fed with the same diet varying the protein source: amaranth, oats and lentils. A sample was taken every seven days and the shell's weight, width and length were measured. Five individuals from each group were sacrificed and the meat from which they were sacrificed was extracted: weight, moisture and protein. The hydrolysis soluble proteins in meat and slime were obtained and the antioxidant activity was measured using the reducing radicals DPPH• and ABTS•. Results: Snail meat was obtained with an increase of more than double in weight when 10% of Am was supplied as a protein source. Likewise, the dimensions of the shell will increase by 5%-11%. In FSM, it was obtained up to 79.8% moisture, 11.2% protein, 1.2% fat and 2.5% collagen. When obtaining snail meat flour, it was reduced to 12±1.9% humidity with up to 24.53 g/g of soluble protein. When hydrolyzing the proteins, it was observed that the peptides obtained presented the IC₅₀ of DPPH scavenging activity of 21.58±2.7, 5.45± 1.8, 12.69±1.7 and IC₅₀ of ABTS removal activity 8.86±0.9, 1.62±0.04, 10.84±1.0, for HFSM, HSMF and SS samples, respectively. Limitations on study/implications: It is necessary to carry out other studies on the functionality of snail meat proteins and thus propose their implementation in food formulations to maximize their commercialization. Findings/conclusions: Feeding snails with amaranth helps to increase the quality of protein in fresh meat and flour. Likewise, requests for soluble proteins from beef, flour and secretion are alternatives for preparing functional foods.

Objective: This work aimed to evaluate the biochemical and functional properties of milk from two goat breeds (Alpina and Toggenburg) which could give goat's milk a higher added value and market, making it an attractive option for milk producers. Design/methodology/approach: Several biochemical analyses were performed to both breed milks: Total Fat (Gerber); Total Protein (Lowry); Lactose (reducing sugars); Fatty acid composition (Mass-mass coupled gas chromatography) and antihypertensive activity (angiotensin-converting enzyme inhibition). To determine possible applications, functional characteristics of yogurt and cheese were also evaluated. Statistical analyses were performed using NCSS software. Results: Fat content of Alpina breed was higher than Toggenburg’s (4.76% vs. 2.96%, α=0.00013), as was lactose (8.26% vs. 5.37%, α=0.003), while Toggenburg presented higher protein content (5.53% vs. 4.77%, α=0.00016). Potential biologically active fatty acids were found in both milks in similar concentrations. Toggenburg milk sowed higher antihypertensive activity than Alpina (100% vs 77.27%), which was maintained and, in some cases, increased, when fermented to obtain different derivatives such as cheese and yogurt. Limitations on study/implications: Further study is still needed to determine the entire biofunctionality of goat’s milk and provide milk producers with options to increase market and added value of their products. Findings/conclusions: Both, Alpina and Toggenburg goat’s milk showed a high Biofunctional potential due to their fat and protein fractions; The fact that biofunctionality can be transferred to derivatives such as yogurt or cheese may increase producers' interest in producing and commercializing it, since the products can be marketed as “functional foods”.

Sustainable hydroponic strawberry cultivation requires precise, real-time management of nutrient solutions to reduce waste and improve resource efficiency for home growers. This work presents an artificial neural network (ANN)-based system that estimates and approximates optimal nutrient formulations for strawberry hydroponics, with a primary focus on nutrient and water savings. The ANN-based system is implemented on hardware for real-time operation and was compared against a traditional PID controller to evaluate performance in nutrient solution management. The ANN receives temperature, humidity, water pH, nutrient concentrations, and lighting as inputs and outputs recommended nutrient solution parameters. Training used gradient descent and reached convergence after an average of 2500 epochs, achieving a mean error of 0.001 and an operating frequency of 84 MHz. Mechanical design was optimized for compact 3D-printable assembly to facilitate adoption by small-scale and domestic producers. The validation with 15 min sampling demonstrated the ability of the system to maintain target nutrient conditions, producing measurable increases in seedling and fruit weight and size while substantially reducing water and nutrient waste. These results indicate that ANN-driven, real-time nutrient estimation can make precision hydroponics more accessible and sustainable for home growers. In the comparative analysis, the ANN-based system demonstrated superior performance compared to the PID controller in maintaining precise nutrient concentrations and reducing resource waste, achieving more accurate tracking of target nutrient levels.