Enzyme assisted fermentation of potato pulp: An effective way to reduce water holding capacity and improve drying efficiency

Umami Enhancing Properties of Enzymatically Hydrolyzed Mycelium of Flammulina velutipes Cultured on Potato Pulp

The aim of this study was to hydrolyze cultivated fungal mycelium and to evaluate the effect on its taste. Potato pulp, a by-product of the potato starch industry, was therefore successfully utilized as a substrate for submerged cultivation of Flammulina velutipes, yielding a product with an estimated fungal content of 83% ± 3%. The fermentation increased the protein content from 5.3 ± 0.4 g/100 g DM to 13.9 ± 0.1 g/100 g DM with a biological protein value of 86. The fermentate was enzymatically hydrolyzed by Corolase APC-peptidase. After optimization of the hydrolysis conditions, a degree of hydrolysis (DH) of 75.1% ± 1.0% was achieved. The protein hydrolysis increased the contents of free glutamate more than 20-fold from 8.7 ± 0.1 mg/L to 188.7 ± 1.2 mg/L. Elevated glutamate levels led to an umami taste perception in aqueous solution and taste-enhancing properties in vegetable broth. Noteworthy, the fermentate itself exhibited an intrinsic peptidase activity. Without addition of auxiliary peptidases, mycelial enzymes caused a DH of 33.9% ± 0.7% and a free glutamate content of 99.1 ± 0.7 mg/L. For these samples, an increase in umami taste was only observed in vegetable broth, but not in water, indicating taste-enhancing properties but low umami taste. In addition to the nutritional and health benefits of fungi, their hydrolysates are of great interest for use as a protein booster with flavor-enhancing properties.

Enhancing drying characteristics and quality of fruits and vegetables using biochemical drying improvers: A comprehensive review

Traditional drying is a highly energy-intensive process, accounting for approximately 15% of total manufacturing cost, it often resulting in reduced product quality due to low drying efficiency. Biological and chemical agents, referred to as biochemical drying improvers, are employed as pretreatments to enhance both drying characteristics and quality attributes of fruits and vegetables. This article provides a thorough examination of various biochemical drying improvers (including enzymes, microorganisms, edible film coatings, ethanol, organic acids, hyperosmotic solutions, ethyl oleate alkaline solutions, sulfites, cold plasma, carbon dioxide, ozone, inorganic alkaline agents, and inorganic salts) and their effects on improving the drying processes of fruits and vegetables. Additionally, it introduces physical drying improvers (including ultrasonic, pulsed electric field, vacuum, and others) to enhance the effects of biochemical drying improvers. Pretreatment with biochemical agents not only significantly enhances drying characteristics but also preserves or enhances the color, texture, and bioactive compound content of the dried products. Meanwhile, physical drying improvers reduce moisture diffusion resistance through physical modifications of the food materials, thus complementing biochemical drying improvers. This integrated approach mitigates the energy consumption and quality degradation typically associated with traditional drying methods. Overall, this review examines the role of biochemical agents in enhancing the drying characteristics and quality of fruits and vegetables, offering a comprehensive strategy for energy conservation and quality improvement.

Machine learning-enhanced modeling and characterization for optimizing dietary Fiber production from Highland barley bran

This study investigated the modification of highland barley bran through co-fermentation of Lactobacillus bulgaricus and Kluyveromyces marxianus, and developed a dynamic prediction model for DF content under these co-fermentation conditions using machine learning algorithms. The results showed that the XGBoost algorithm could predict changes in the DF component content (R2 = 0.9553(SDF/IDF), RMSE = 0.0464.) and identify optimal fermentation conditions. Under these optimal conditions, both strains exhibited synergistic effects, where the lactic acid produced by Lactobacillus bulgaricus and β-glucosidase produced by Kluyveromyces marxianus may facilitate IDF decomposition and conversion, resulting in a maximum SDF/IDF ratio of 0.6911. This led to a 27.65 % reduction in IDF content and a 19.11 % increase in SDF content. Moreover, the physicochemical and functional properties of DF were enhanced after co-fermentation. The structure of DF became looser and more porous, its thermal stability improved, and its water-holding, oil-holding, and swelling capacities increased by 53.54 %, 16.11 %, and 44.96 %, respectively, compared with the unfermented counterpart; in terms of adsorption characteristics, its glucose, cholesterol and nitrite adsorption capacities were also significantly improved. According to in vitro gastrointestinal simulated digestion, digestion would have a great impact on the fermented DF, which showed good antioxidant properties during the intestinal digestion stage.

Development of thermoultrasound assisted blanching to improve enzyme inactivation efficiency, drying characteristics, energy consumption, and physiochemical properties of sweet potatoes

Thermoultrasound (USB) as a promising alternative to traditional hot water (HWB) blanching was employed to blanch sweet potatoes and its influence on enzyme activity, drying behavior, energy consumption and physiochemical properties of sweet potatoes were investigated. Results showed that successive increases in blanching temperature and time resulted in significant (p < 0.05) decreases in PPO and POD activities. Compared to HWB, USB led to more effective drying by promoting texture softening, moisture diffusion, microstructure alterations, and microchannels formation, which significantly reduced energy consumption and improved the overall quality of the dried sample. Specifically, USB at 65 °C for 15 min improved water holding capacity and ABTS, while USB at 65 °C for 30 min improved color (more red and yellow), total phenolic content, total carotenoid content, and DPPH. Unfortunately, blanching process showed detrimental effects on the amino acid composition of dried samples. Overall, the development of thermoultrasound assisted blanching for sweet potatoes has the potential to revolutionize the processing and production of high-quality sweet potato products, while also improving the sustainability of food processing operations.

Moisture variation analysis of the green plum during the drying process based on low-field nuclear magnetic resonance

Green plums were dried at 50, 60, 70, and 80 ℃ to study the dynamic changes of internal moisture during the drying process. Low-field nuclear magnetic resonance (LF-NMR) was used to study the dynamic changes across the T₂ relaxation spectrum, while magnetic resonance imaging (MRI) provided visualization of the plums throughout the process. The results indicate a negative linear relationship between the lost moisture of the plums (p < 0.05) as drying time increased. Relaxation times T₂₁ , T_22, and T₂₃ , and the peak areas of A₂₁ and A₂₃ decreased significantly during the drying process. The MRI results also show that the brightness of the images decreased as the drying time increased, indicating that the higher the temperature, the greater the water loss inside the plums. Color measurements demonstrated that the high temperature dried plums had better sensory quality. Correlation analysis implies a strong positive relationship between A₂₃ and A_total and water content, with coefficients of 0.958 and 0.936, respectively. Principal component analysis results show that the drying temperature has a significant effect on the sample's internal moisture release. LF-NMR is a fast, convenient, and feasible technique for monitoring the moisture variation of green plums during the drying process. PRACTICAL APPLICATION: Low-field nuclear magnetic resonance (LF-NMR) was used to study the moisture dynamic changes of green plums across the T₂ relaxation spectrum, while magnetic resonance imaging (MRI) provided visualization of plums throughout the process. The drying temperature has a significant effect on the green plum's internal moisture release and may affect the quality of the plums. LF-NMR might be a complementary technique in monitoring the moisture variation of green plums during the drying process.

Autoclaving and extrusion improve the functional properties and chemical composition of black bean carbohydrate extracts

Common beans (Phaseolus vulgaris L.) are rich in starch with a high content of amylose, which is associated with the production of retrograded and pregelatinized starch through thermal treatments. The purpose of this study was to evaluate the composition, morphology, thermal, functional, and physicochemical properties of carbohydrate extracts (CE) obtained from autoclaved (100 and 121 °C) and extruded (90, 105, and 120 °C) black beans. After evaluation of the functional properties, the CE from autoclaved beans at 100 °C for 30 min and 121 °C for 15 min 2×, and extruded beans at 120 °C and 10 rpm, were selected to continue the remaining analysis. Autoclaving treatments at 100 °C for 30 min and 121 °C for 15 min 2× showed a reduction of resistant starch by 14.4% and 26.6%, respectively, compared to dehulled raw bean CE. Meanwhile, extrusion showed a reduction in resistant starch of 54.2%. Autoclaving and extrusion treatments also decreased the dietary fiber content. Extrusion reduced almost entirely the content of α-galactooligosaccharides, in comparison to dehulled raw bean CE. The results showed differences in color and granule morphology. The onset, peak, and conclusion temperatures, transition temperature range, and enthalpy of autoclaved and extruded bean CE were lower than dehulled raw bean CE. The CE from autoclaved and extruded beans contain retrograded and pregelatinized starch, which could be incorporated in food products as a thickening agent for puddings, sauces, creams, or dairy products. PRACTICAL APPLICATION: Thermally treated black bean carbohydrate extracts are rich in starch, fiber, and protein. Because these extracts are already cooked, they can be added to products that do not require a thermal process such as puddings, sauces, creams, or dairy products, acting as a thickening agent.

Study on rapid drying and spoilage prevention of potato pulp using solid-state fermentation with Aspergillus aculeatus

Effects of solid-state fermentation on rapid drying and spoilage prevention of potato pulp were evaluated. Pectin hydrolyzing and antibacterial ability of pectinase-secreting Aspergillus aculeatus and Bacillus subtilis were compared. A. aculeatus grew better in potato pulp, with highest pectinase yield of 342.71 ± 5.09 U/mL and rapid pH reduction to 3.76 ± 0.01. Next generation sequencing showed that the abundance of genera Candida and Enterobacter, which probably caused undesirable fermentation and spoilage, were significantly reduced after inoculation with A. aculeatus. In addition, fermentation with A. aculeatus significantly reduced water holding capacity from 16.63 ± 0.36 g/g to 7.78 ± 0.12 g/g, which resulted in lower viscosity and water binding capacity, and concomitantly significantly decreased moisture content from 76.05 ± 0.24% to 12.95 ± 0.19% after filtration and airflow drying. These results suggested that solid-state fermentation might be a promising technology for efficient processing and utilization of potato pulp.

Study on quality characteristics of cassava flour and cassava flour short biscuits

In this paper, the basic components, nutrient composition, and processing characteristics of cassava flour were determined. In addition, the effects of xanthan gum and inulin on the pasting properties, microstructure, and thermal properties of cassava flour were studied. Biscuits were prepared using cassava flour as the main raw material and the optimal technology and formula for the biscuits were determined by single-factor and orthogonal tests. The effects of xanthan gum and inulin on the quality of cassava flour short biscuits were also investigated, and volatile components in the biscuits were determined using electronic nose technique. The addition of xanthan gum improved the pasting properties and microstructure of cassava flour, and improved the taste and increased hardness and brittleness of the biscuits, making their quality similar to that of commercially available short biscuits. The addition of inulin inhibited the setback of starch and improved starch gelatinization. However, inulin was not suitable for processing of cassava flour biscuits as it decreased their hardness, brittleness, and taste. The optimal formula and baking conditions of cassava flour short biscuits were as follows: cassava flour 100 g, water 24 g, shortening 25 g, sugar 30 g, baking powder 0.6 g, salt 1 g, and egg 25 g; the surface fire and primer fire temperatures were 180°C, and the baking time was 9 min. In addition, although the main aroma volatile components present in cassava flour and low gluten wheat flour short biscuits were similar, the proportions of each component were different.