Sensory evaluation and glycaemic index of a food developed with flour from whole (pulp and peel) overripe banana (Musa cavendishii) discards

Heterologous Expression of Thermotolerant α-Glucosidase in Bacillus subtilis 168 and Improving Its Thermal Stability by Constructing Cyclized Proteins

α-glucosidase is an essential enzyme for the production of isomaltooligosaccharides (IMOs). Allowing α-glucosidase to operate at higher temperatures (above 60 °C) has many advantages, including reducing the viscosity of the reaction solution, enhancing the catalytic reaction rate, and achieving continuous production of IMOs. In the present study, the thermal stability of α-glucosidase was significantly improved by constructing cyclized proteins. We screened a thermotolerant α-glucosidase (AGL) with high transglycosylation activity from Thermoanaerobacter ethanolicus JW200 and heterologously expressed it in Bacillus subtilis 168. After forming the cyclized α-glucosidase by different isopeptide bonds (SpyTag/SpyCatcher, SnoopTag/SnoopCatcher, SdyTag/SdyCatcher, RIAD/RIDD), we determined the enzymatic properties of cyclized AGL. The optimal temperature of all cyclized AGL was increased by 5 °C, and their thermal stability was generally improved, with SpyTag-AGL-SpyCatcher having a 1.74-fold increase compared to the wild-type. The results of molecular dynamics simulations showed that the RMSF values of cyclized AGL decreased, indicating that the rigidity of the cyclized protein increased. This study provides an efficient method for improving the thermal stability of α-glucosidase.

The effect of enzymatically treated ripe banana flour on the sensory quality and glycemic response of banana-wheat flour composite muffins

Banana are the most consumed fruit worldwide, due to their good flavour and nutritional characteristics; however, when the banana is very or over ripe, the acceptability by the consumer decreases, and in many cases the fruit must be discarded. An alternative to consume these fruits and revalue these discards is their use as a food ingredient. The presence of bioactive compounds gives added value to this type of ingredients; therefore, using methods, such as enzymatic treatment, that increase their presence is of great interest. In this work a commercial pectinase (Viscozyme L) was applied in a flour produced from whole overripe banana; then, the treated flour was used to elaborate a baked product. The aim of this work was to evaluate the effect of the incorporation of an enzymatic treated overripe banana (Musa cavendishii) flour in the sensory evaluation of muffins and, to stablish if the consumption of this food produce an effect on glycaemic response against a control food. The enzyme application produces an increment of 52% of antioxidant activity with a value of 12,791.6 μmolTE/100 g, and a presence of 4.5% RS instead 3.5% in non-treated flour. The sensory evaluation study was conducted with 4 products, using an untrained panel; selecting a muffin with 50% of wheat flour replaced with the banana treated one. This one contains 9.49% of dietary fibre. The glycaemic response study was conducted with 20 healthy volunteers, using as control a 100% wheat flour product, non-observing significant differences between both products. This work contributes to the knowledge about the potential use of a food discard as an ingredient of a food of massive consumption.

Sustainable Use of Fruit and Vegetable By-Products to Enhance Food Packaging Performance

Fruit and vegetable by-products are the most abundant food waste. Industrial processes such as oil, juice, wine or sugar production greatly contribute to this amount. These kinds of residues are generally thrown away in form of leftover and used as feed or composted, but they are a great source of bioactive compounds like polyphenols, vitamins or minerals. The amount of residue with potential utilization after processing has been estimated in millions of tons every year. For this reason, many researchers all around the world are making great efforts to valorize and reuse these valuable resources. Of greatest importance is the by-product potential to enhance the properties of packaging intended for food applications. Therefore, this overview collects the most recent researches dealing with fruit and vegetable by-products used to enhance physical, mechanical, antioxidant and antimicrobial properties of packaging systems. Recent advances on synthetic or bio-based films enriched with by-product components are extensively reviewed, with an emphasis on the role that by-product extracts can play in food packaging materials.

Development and characterization of blends formulated with banana peel and banana pulp for the production of blends powders rich in antioxidant properties

The food product industry is increasingly looking for foods with nutritional properties that can provide health benefits. Additionally, a challenge for the food industry is the use of all raw materials. For these reasons, banana peel that is a raw material from Banana (Musa spp.) fruit emerges as potential for new food product development. Here, we developed powder blends using a lyophilization process for the preparation of flour to potential use in cookies, bread, and pasta products. Three formulations were designed; the main difference in the formulations was the use of banana peel concentration. Our results showed that blends produced with banana peel presented physical-chemical properties considered suitable for use in food industry. Moreover, the evaluated morphological parameters reveal the properties of the powders. The blends formulated with banana peel have more antioxidant properties, showing that the banana peel may be an attractive option to generate powders with high antioxidant properties.

Heterologous Expression of a Thermostable α-Glucosidase from Geobacillus sp. Strain HTA-462 by Escherichia coli and Its Potential Application for Isomaltose⁻Oligosaccharide Synthesis

Isomaltose-oligosaccharides (IMOs), as food ingredients with prebiotic functionality, can be prepared via enzymatic synthesis using α-glucosidase. In the present study, the α-glucosidase (GSJ) from Geobacillus sp. strain HTA-462 was cloned and expressed in Escherichia coli BL21 (DE3). Recombinant GSJ was purified and biochemically characterized. The optimum temperature condition of the recombinant enzyme was 65 °C, and the half-life was 84 h at 60 °C, whereas the enzyme was active over the range of pH 6.0-10.0 with maximal activity at pH 7.0. The α-glucosidase activity in shake flasks reached 107.9 U/mL and using 4-Nitrophenyl β-D-glucopyranoside (pNPG) as substrate, the K_m and Vmax values were 2.321 mM and 306.3 U/mg, respectively. The divalent ions Mn²⁺ and Ca²⁺ could improve GSJ activity by 32.1% and 13.8%. Moreover, the hydrolysis ability of recombinant α-glucosidase was almost the same as that of the commercial α-glucosidase (Bacillus stearothermophilus). In terms of the transglycosylation reaction, with 30% maltose syrup under the condition of 60 °C and pH 7.0, IMOs were synthesized with a conversion rate of 37%. These studies lay the basis for the industrial application of recombinant α-glucosidase.