Residence Time Distribution (RTD) in a Single Screw Extrusion of African Breadfruit Mixtures

Study on the Residence Time and Texture Prediction of Pea Protein Extrusion Based on Image Analysis

This paper initially involves three main processing parameters: screw speed, feeding speed, and initial material moisture content, exploring the RTD of materials inside the extruder barrel under varying parameters and clarifying the impact of parameter variations on RTD. Finally, machine vision technology was utilized to link extruded product images to texture features, and a texture prediction model based on image features was established using a Back Propagation (BP) neural network. Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) were applied to optimize the BP neural network. The results indicate that the feeding speed has a stronger impact than the screw speed on the extrusion process, and an increase in the initial material moisture content tends to shorten the RTD. Specifically, an increase in screw speed results in a denser product structure, while higher feeding speeds lead to reduced pore size in the microstructure. As the initial material moisture content increased from 55% to 70%, the average residence time MRT decreased from 265.21 s to 166.62 s. Additionally, elevated moisture content causes a more porous microstructure. After optimizing the texture prediction model of extruded products through the application of Particle Swarm Optimization and Genetic Algorithm models, it was discovered that the Genetic Algorithm was more effective in reducing errors (p < 0.05) than the Particle Swarm Optimization algorithm. It was found that the Particle Swarm Optimization model exhibited better prediction performance. The results of the prediction indicated a significant association between the image features of the product and hardness, resilience, and chewiness, as corroborated by correlation coefficients of 0.93913, 0.94040, and 0.94724, respectively.

Effect of processing and substitution levels of Ukwa (Treculia africana) on the anti-nutrient factors, in-vitro starch and protein digestibility and total essential amino-acid content of snack bars

Introduction

Ukwa (Treculia africana) is an indigenous edible seed. It is a strategic store of vital food nutrients that are available during a specific crucial time of the year when reliable sources of these nutrients are under cultivation and extremely scarce. In the past, only poor rural residents used to eat it, but today it is not only a specialty meal enjoyed by Nigeria's elite and metropolitan residents but also a source of foreign exchange.

Methods

In this study, Ukwa was processed into whole, dehulled, malted and defatted flours. Maize and coconut flours were blended with the respective Ukwa flours at the ratio of 0:95:5, 20:75:5, 25:70:5, 30:65:5, 35:60:5 and 95:0:5 for Ukwa flour:Maize flour:Coconut grits respectively for development of snack bars. A two-factor factorial experiment in a completely randomized block design was applied for the study of the effect of processing, substitution levels of Ukwa flour and the interaction of the two variables on the responses analyzed. Anti-nutrient content and proximate compositions of the flours were determined using standard procedures.

Results

Processing significantly reduced the anti-nutrient content and increased protein content of Ukwa flours. Up to 51.72% reduction of tannin was obtained by dehulling. Defatting, malting and dehulling resulted in 18.75, 34.37 and 65.62% reduction respectively in oxalate content. Highest reduction was obtained by dehulling, and was 70.69% in phytate, 79.95% in saponin, and 48.17% in trypsin inhibitor activity. Crude protein content of snack bars had 16.16 to 25.46% substitution main effect, and 19.43 to 22.65% processing main effect. In-vitro protein and starch digestibility increased with processing and decreased with increase in substituted level of Ukwa in the blend. Improvement, up to 9.97% by dehulling, 9.86% by malting and 8.64% by defatting, was recorded in in-vitro protein digestibility. An increase of 3.00 to 24.10% by defatting, 5.90 to 29.09% by malting and 9.70 to 31.80% by dehulling was recorded in in-vitro starch digestibility.

Discussion

Our study revealed that, all the processing methods adopted reduced the anti-nutrient content of ukwa flours. Protein content and total essential amino-acid (TEAA) showed significant increase with increased substituted level of ukwa flour. In-vitro protein and starch digestibility decreased with increase substituted level of ukwa flour. Snack bars formulated with 20% Ukwa showed the highest in-vitro starch and protein digestibility irrespective of the method of processing. Malted Ukwa based snack bars recorded the highest values of TEAA. Processing of this nutritious seeds and use of its flour to develop snack bars could enhance utilization and give convenience to consumers and encourage extensive farming of the crop.

Extraction, Biochemical Characterization, and Health Effects of Native and Degraded Fucoidans from Sargassum crispifolium

In the current investigation, a native crude fucoidan (Ex) was extracted from Sargassum crispifolium, pretreated by single-screw extrusion, and two degraded fucoidans, i.e., ExAh (degradation of Ex by ascorbic acid) and ExHp (degradation of Ex by hydrogen peroxide), were obtained. The extrusion pretreatment increased the extraction yield of fucoidan by approximately 1.73-fold as compared to the non-extruded sample. Among Ex, ExAh, and ExHp, their molecular weight and chemical compositions varied, but the structural features were similar. ExHp possessed the greatest antioxidant activities among the extracted fucoidans. According to the outcome, ExAh exhibited the maximum immune promoting effects via enhanced NO, TNF-α, IL-1β, IL-6, and IL-10 secretion. Thus, both ExHp and ExAh may potentially be used as an effective antioxidant and as immunostimulant agents, which could be of great value in the development of food and nutraceutical products.

Validation of process technologies for enhancing the safety of low-moisture foods: A review

The outbreaks linked to foodborne illnesses in low-moisture foods are frequently reported due to the occurrence of pathogenic microorganisms such as Salmonella Spp. Bacillus cereus, Clostridium spp., Cronobacter sakazakii, Escherichia coli, and Staphylococcus aureus. The ability of the pathogens to withstand the dry conditions and to develop resistance to heat is regarded as the major concern for the food industry dealing with low-moisture foods. In this regard, the present review is aimed to discuss the importance and the use of novel thermal and nonthermal technologies such as radiofrequency, steam pasteurization, plasma, and gaseous technologies for decontamination of foodborne pathogens in low-moisture foods and their microbial inactivation mechanisms. The review also summarizes the various sources of contamination and the factors influencing the survival and thermal resistance of pathogenic microorganisms in low-moisture foods. The literature survey indicated that the nonthermal techniques such as CO₂ , high-pressure processing, and so on, may not offer effective microbial inactivation in low-moisture foods due to their insufficient moisture content. On the other hand, gases can penetrate deep inside the commodities and pores due to their higher diffusion properties and are regarded to have an advantage over thermal and other nonthermal processes. Further research is required to evaluate newer intervention strategies and combination treatments to enhance the microbial inactivation in low-moisture foods without significantly altering their organoleptic and nutritional quality.

Fish Collagen: Extraction, Characterization, and Applications for Biomaterials Engineering

The utilization of marine-based collagen is growing fast due to its unique properties in comparison with mammalian-based collagen such as no risk of transmitting diseases, a lack of religious constraints, a cost-effective process, low molecular weight, biocompatibility, and its easy absorption by the human body. This article presents an overview of the recent studies from 2014 to 2020 conducted on collagen extraction from marine-based materials, in particular fish by-products. The fish collagen structure, extraction methods, characterization, and biomedical applications are presented. More specifically, acetic acid and deep eutectic solvent (DES) extraction methods for marine collagen isolation are described and compared. In addition, the effect of the extraction parameters (temperature, acid concentration, extraction time, solid-to-liquid ratio) on the yield of collagen is investigated. Moreover, biomaterials engineering and therapeutic applications of marine collagen have been summarized.

Increasing the bio-electrochemical system performance in azo dye wastewater treatment: Reduced electrode spacing for improved hydrodynamics

The electrodes spacing would exert a pronounced effect on bio-electrochemical systems (BESs) performance, especially for the scaling-up of reactors and practical applications. In this study, we traced the effect of electrode spacing on wastewater treatment performances from the aspects of hydrodynamics and electrochemical characteristics. Three series of folded stainless steel mesh (f-SSM) electrodes with electrode spacing of 2, 4 and 8mm were designed for azo dye (acid orange 7 (AO7)) wastewater treatment. Results showed that BES with electrode spacing of 2mm (R_S2) obtained the highest efficiencies of AO7 decolorization (90.9±0.4%) and COD removal (36.8±3.8%) at HRT of 8h, which was 30.7% and 15.2% higher than that in BES with electrode spacing of 8mm (R_S8), respectively. Moreover, the relationship between pollutants removal, internal resistance and hydrodynamics of BESs with different electrode spacing supported the hydrodynamics was significantly influence the pollutants removal performance.

Corrugated stainless-steel mesh as a simple engineerable electrode module in bio-electrochemical system: Hydrodynamics and the effects on decolorization performance

The application of bio-electrochemical system (BESs) is strongly depended on the development of the engineering applicable electrode. Here we described an economical and readily processable electrode module with three-dimensional structure, the corrugated stainless-steel mesh electrode module (c-SMEM). This novel developed electrode module was demonstrated to provide a good hydrodynamic characteristic and significantly enhanced the decolorization performance of the BES when serving for treating azo dye (acid orange 7, AO7) containing wastewater. Compared to the conventional planar electrodes module (p-SMEM), c-SMEM was found to prolong the mean residence time (MRT_θ) of AO7 and change the flow pattern closer to the plug flow. As a result, the maximum enhancement of the volumetric decolorization rate (vDR) can reach to 255%, even when the c-SMEM and p-SMEM have the same electrode surface area. In addition, a techno-economic analysis model was established to elucidated the effects of the decolorization performance and the material cost on the initial capital cost, which revealed the BES with c-SMEM could be economically comparable to or even better than the traditional bio-decolorization technologies. These results suggest c-SMEM holds great potential for engineering application, which may help paving the way of applying BES at large-scale.

Effects of fermentation time on the functional and pasting properties of defatted Moringa oleifera seed flour

Effects of fermentation time on the functional and pasting properties of defatted Moringa oleifera seed flour was examined. Moringa seeds were fermented naturally at 0, 12, 24, 48 and 72 h; oven dried at 60°C for 12 h; milled into five different flour samples for each fermentation time and defatted. The functional and pasting properties of the samples were determined. The result shows significant increase in the water absorption capacity, oil absorption capacity, foaming capacity and emulsifying capacity with increase in fermentation time. However, there was a significant decrease in bulk density (0.53–0.32 g/cm³) and dispersibility (36.00–20.50%) with an increase in fermentation time. There were significant increase in peak viscosity, trough, breakdown, final viscosity, and set back with increasing fermentation time. The swelling power and solubility of fermented Moringa seed flour was significantly affected.