Dilute acid hydrolysis of spoiled wheat grains: Analysis of chemical, rheological and spectral characteristics

Identification and characterization of a potential strain for the production of polyhydroxyalkanoate from glycerol

While poly (3-hydroxybutyrate) (PHB) holds promise as a bioplastic, its commercial utilization has been hampered by the high cost of raw materials. However, glycerol emerges as a viable feedstock for PHB production, offering a sustainable production approach and substantial cost reduction potential. Glycerol stands out as a promising feedstock for PHB production, offering a pathway toward sustainable manufacturing and considerable cost savings. The identification and characterization of strains capable of converting glycerol into PHB represent a pivotal strategy in advancing PHB production research. In this study, we isolated a strain, Ralstonia sp. RRA (RRA). The strain exhibits remarkable proficiency in synthesizing PHB from glycerol. With glycerol as the carbon source, RRA achieved a specific growth rate of 0.19 h-1, attaining a PHB content of approximately 50% within 30 h. Through third-generation genome and transcriptome sequencing, we elucidated the genome composition and identified a total of eight genes (glpR, glpD, glpS, glpT, glpP, glpQ, glpV, and glpK) involved in the glycerol metabolism pathway. Leveraging these findings, the strain RRA demonstrates significant promise in producing PHB from low-cost renewable carbon sources.

Bacterial cellulose/gum Arabic composite production by in-situ modification from lavender residue hydrolysate

In this study, bacterial cellulose/gum Arabic composite (BC/GA) was synthesized by in-situ modification from lavender residue hydrolysate for the first time. The in-situ modification with GA adding showed great beneficial effect for BC/GA synthesis. Both the product (BC or BC/GA) yield and the product (BC or BC/GA) production per sugars consumption increased greatly by the in-situ modification when compared with the fermentation without GA adding (2.90 g/L vs. 0.91 g/L, and 0.461 g/g vs. 0.138 g/g). It is hypothesized that the combination of BC and GA is the main mechanism for the beneficial effect of the in-situ modification, and the scanning electron microscope (SEM) images confirmed this hypothesis. GA adding showed little effect on the rheological properties of lavender residue hydrolysate, and this environment was suitable for the combination of BC and GA. The in-situ modification had an obvious influence on the crystallinity index and the thermal stability of BC/GA, but affected little on its functional groups and cellulose structural framework. Besides BC/GA synthesis and structure, the in-situ modification could also alter the texture properties of BC/GA. Overall, this study can offer some useful information for the biochemical conversion from green and cost-effective lavender residue hydrolysate to attractive biomaterial BC/GA.

Evaluating the Potential of Newly Developed Energy Cane Clones for First- and Second-Generation Ethanol Production

The rapid increases in fuel ethanol demand and food security concerns have driven the need for diverse feedstocks in the ethanol production process. Energy cane is an energy crop that is an ideal sustainable biofuel feedstock. The present study evaluated ethanol production of the juice and bagasse of two newly developed energy cane clones, TByEFC08-0035 and TByEFC10-0004. The results of the chemical composition analyses of the juice and bagasse samples revealed that the two energy cane clones contained high contents of both sucrose (15.36–17.95%) and fiber (13.44–24.16%). The maximum ethanol concentrations from the juice on a laboratory scale (87.10 g/L) and on an agronomic scale (1211.76 kg/ha) were recorded for TByEFC10-0004 fermented with a new isolate Kluyveromyces marxianus SJT83, whereas the maximum ethanol concentrations from bagasse on a laboratory scale (9.81 g/L) and on an agronomic scale (790.68 kg/ha) were reached with TByEFC08-0035 fermented with Scheffersomyces shehatae TTC79. The total ethanol yields from the juice and bagasse samples per cultivation area of both energy cane clones were in the range 1294.23–1469.14 kg/ha, being 1.70–1.93 and 1.08–1.23 times higher than the control energy cane Biotec2 variety and the commercial sugar cane Khon Kaen3 variety, respectively. This study revealed the potential of the energy cane clones TByEFC08-0035 and TByEFC10-0004 currently being developed as sugar and lignocellulose substrates for first- and second-generation ethanol industry applications.

In vitro digestion of tofu with different textures using an artificial gastric digestive system

Two kinds of tofu with obvious differences in texture ["GDL" and "CaSO₄", standing for tofus made with the application of either glucono-δ-lactone (GDL) or calcium sulfate, with measured hardness 23.1 ± 3.3 g and 105.2 ± 25.1 g, respectively] were used as to investigate the in vitro progress and extent of tofu digestion, using an independently-developed artificial gastric digestion system (AGDS). The particle size distributions of both CaSO₄ and GDL tofu shifted towards smaller particles as the digestion time increased, while the viscosity of the gastric digesta also increased. Tofu proteins were hydrolyzed in the simulated stomach, with GDL tofu showing a higher hydrolysis rate, based on the temporal evolution of SDS-PAGE bands, and had a higher amino acids accumulation than CaSO₄ tofu at the end of gastric digestion. In the absence of peptic enzymes, the protein was acidically-hydrolyzed, but the degree of hydrolysis was much lower than in the presence of enzymes; these findings are in accord with the changes in microstructure observed by scanning electron microscopy. The results indicated that the in vitro extent of tofu digestion is related to its hardness, which is in turn related to its microstructure; they also indicated the potential of our developed in vitro dynamic stomach in studying semi-solid foods.

Biochar derived from fruit by-products using pyrolysis process for the elimination of Pb(II) ion: An updated review

Water pollution is one of the most concerning global environmental problems in this century with the severity and complexity of the issue increases every day. One of the major contributors to water pollution is the discharge of harmful heavy metal wastes into the rivers and water bodies. Without proper treatment, the release of these harmful inorganic waste would endanger the environment by contaminating the food chains of living organisms, hence, leading to potential health risks to humans. The adsorption method has become one of the cost-effective alternative treatments to eliminate heavy metal ions. Since the type of adsorbent material is the most vital factor that determines the effectiveness of the adsorption, continuous efforts have been made in search of cheap adsorbents derived from a variety of waste materials. Fruit waste can be transformed into valuable products, such as biochar, as they are composed of many functional groups, including carboxylic groups and lignin, which is effective in metal binding. The main objective of this study was to review the potential of various types of fruit wastes as an alternative adsorbent for Pb(II) removal. Following a brief overview of the properties and effects of Pb(II), this study discussed the equilibrium isotherms and adsorption kinetic by various adsorption models. The possible adsorption mechanisms and regeneration study for Pb(II) removal were also elaborated in detail to provide a clear understanding of biochar produced using the pyrolysis technique. The future prospects of fruit waste as an adsorbent for the removal of Pb(II) was also highlighted.

Strategies and advances in the pretreatment of microalgal biomass

Modification of structural components, especially the cell wall, through adequate pretreatment strategies is critical to the bioconversion efficiency of algal biomass to biorefinery products. Over the years, several physical, physicochemical, chemical and green pretreatment methods have been developed to achieve maximum productivity of desirable by-products to sustain a circular bioeconomy. The effectiveness of the pretreatment methods is however, species specific due to diversity in the innate nature of the microalgal cell wall. This review provides a comprehensive overview of the most notable and promising pretreatment strategies for several microalgae species. Methods including the application of stress, ultrasound, electromagnetic fields, pressure, heat as well as chemical solvents (ionic liquids, supercritical fluids, deep eutectic solvents etc.) have been detailed and analyzed. Enzyme and hydrolytic microorganism based green pretreatment methods have also been reviewed. Metabolic engineering of microorganisms for product specificity and lower inhibitors can be a future breakthrough in microalgal pretreatment.

Pyrolysis of almond (Prunus amygdalus) shells: Kinetic analysis, modelling, energy assessment and technical feasibility studies

The aim of this work was to study the thermogravimetric analysis through the pyrolysis of almond (Prunus amygdalus) shells for evaluating its potential for bioenergy at different heating rates (10, 25, and 50 K min^-1). The activation energy values for the process were of the range of 153.0, 152.02, and 152.73 kJ mol^-1 as calculated by Kissenger-Akahira-Sunrose (KAS), Ozawa-Flynn-Wall (OFW) and Starink models respectively. The change in the Gibbs free energy was ~181 kJ mol^-1. Diffusion-based reaction, followed by the chemical reaction mechanism,was dominant thermal degradation as envisaged by the Coats-Redfern method. The validation of the experiments was accomplished through the artificial neural network, reiterating its further usage in any conversional studies of biomass. A difference of < 10 kJ mol^-1 between the values of activation energy and enthalpy of the degradation reaction indicated favourable product formation. The results offer potential application of almond shells for energy production through pyrolysis.

Physicochemical and Thermal Characteristics of Onion Skin from Fifteen Indian Cultivars for Possible Food Applications

Every year tons of onion waste is produced worldwide. The dried outer onion skin contributed up to 70% of this waste. Outer-dried skins of fifteen prominent onion cultivars from India were selected for the study. A comparative study was done for proximate profiling, thermal characteristics, functional grouping, and mineral contents. Skin of cv. “NHRDF Red” contained the highest amount of crude protein (5.97 ± 0.15 g/100 g), ash (12.24 ± 0.59 g/100 g), and fiber (8.28 ± 0.20 g/100 g), whereas cv. “Pusa Red” possessed the highest amount of total fat (0.47 ± 0.02 g/100 g) and the maximum carbohydrates (76.66 ± 0.56 g/100 g) were found in “Pusa Riddhi.” Mineral analysis showed that cv. “NHRDF Red” had the maximum concentration of all 9 minerals along with sulphur content. Fourier transform infrared spectroscopy analysis explored the various metabolites present in each cultivar. The thermal analysis explored cv. “Agrifound Dark Red” as highly thermally stable having 70.98% residual mass. The lowest Tg temperature range was found between 64.4°C and 90.6°C for “Agrifound Dark Red.” Skin of cv. “NHRDF Red” was reported as the best source of protein, fiber, and minerals, which may be utilized for developing a food product.

Evaluation of Chemical, Functional, Spectral, and Thermal Characteristics of Sargassum wightii and Ulva rigida from Indian Coast

Usage of seaweeds as a functional food/food ingredient is very limited due to paucity of scientific information about variations in the nutritional composition of seaweeds under diverse climatic conditions. Sargassum wightii and Ulva rigida seaweeds are found abundantly on the Southern Indian coastline and were thoroughly evaluated in this work. Crude fiber and lipid of S. wightii were higher (24.93 ± 0.23% and 3.09 ± 0.41%, respectively) as compared to U. rigida; however, U. rigida had higher crude protein content (27.11 ± 0.62%). Evaluation of mineral and CHNS content indicated that the concentration of potassium, magnesium, and calcium was 1.36 ± 0.08 mg/g, 8.39 ± 0.80 mg/g, and 14.03 ± 3.46 mg/g, respectively, that was higher in the S. wightii, whereas U. rigida contained higher value of iron, carbon, and sulphur (0.70 ± 0.13 mg/g, 37.72 ± 4.63%, and 2.61 ± 0.16%, respectively). Swelling capacity (19.42 ± 0.00 mL/g DW to 22.66 ± 00 mL/g DW), water-holding capacity (6.15 ± 0.08 g/g DW to 6.38 ± 0.14 g/g DW), and oil-holding capacity (2.96 ± 0.13 g/g DW) of U. rigida were significantly ( $p<0.05$ ) higher as compared to S. wightii. It was observed from DSC thermograms that S. wightii can be safely processed for food formulations even at a temperature of 134°C. The thermograms also revealed changes in the sulphated polysaccharide (fucoidan) profile due to the presence of hydroxyl and carboxyl groups with denaturation of proteins. TGA of S. wightii and U. rigida showed degradation temperature within the range of 200–300°C due to divergent polysaccharide compositions. FTIR spectroscopy suggested the presence of phenolic groups in both seaweeds (at 1219 cm−1). Results of the study suggested that the manufacturing of functional food products from seaweeds could be beneficial and may aid in social upliftment of cultivators/fishermen.

Technologies for disinfection of food grains: Advances and way forward

Growing demand from the consumers for minimally processed and high-quality food products has raised the scientific quest for foods with improved natural flavours in conjunction with a restricted supplement of additives. In this context, achieving quality and safe food grains and the identification of suitable processing and disinfection technologies have also become the key issues. Microbial contamination is one of the major reasons responsible for the spoilage of food grains. Various sources of contamination such as air and water (both contaminated with dust and dirt), animals (insects, birds, rodents), environmental conditions (rainfall, drought, temperature), unhygienic handling, harvesting, processing equipment and improper storage conditions are responsible for the microbial spoilage of food grains. In order to maintain the food grains safe and un-contaminated, several food processing technologies have been explored and implemented, with the ultimate purpose of maintaining the safety, freshness and nutritional attributes of the food products. Among these technologies, microwave, radiofrequency, infrared, ohmic heating, novel drying methods along with non-thermal methods such as cold plasma, irradiation, ozonation and nanotechnology have attracted much attention because of considerable reduction in the overall processing time with minimum energy consumption. This review aims to discuss the advances involving the said technologies for controlling the microbial contamination of food grains in accordance with their inactivation. Current research status of the thermal and non-thermal emerging technologies for the preservation of food grains as well as perspectives for further research in this area are also elaborated in detail.

Sustainable processing of food waste for production of bio-based products for circular bioeconomy

Sustainable development of circular bioeconomy concept is only possible upon adopting potential advanced technologies for food waste valorization. This approach can simultaneously answer resources and environmental challenges incurred due to capital loss and greenhouse gases accumulation. Food waste valorization opens new horizons of economical growth, bringing waste as an opportunity feedstock for bio processes to synthesize biobased products from biological source in a circular loop. Advanced technologies like Ultrasound assisted extraction, Microwave assisted extraction, bioreactors, enzyme immobilization assisted extraction and their combination mitigates the global concern caused due to mismanagement of food waste. Food waste decomposition to sub-zero level using advanced techniques fabricates food waste into bio-based products like bioactive compounds (antioxidants, pigments, polysaccharides, polyphenols, etc.); biofuels (biodiesel, biomethane, biohydrogen); and bioplastics. This review abridges merits and demerits of various advanced techniques extended for food waste valorization and contribution of food waste in revenue generation as value added products.

Harnessing fruit waste for poly-3-hydroxybutyrate production: A review

Poly-3-hydroxybutyrate is a biopolymer which has shown tremendous potential for replacing conventional petroleum-based plastics for plummeting the plastic pollution problem. However, the production cost of PHB is high which makes it less attractive for commercial use. To tackle this challenge, various researchers suggest the search for low-cost substrates and energy efficient technologies for PHB production. In this regard, the waste generated from fruit processing industries or fruit wastes could be pre-processed and fermented for effectively generating PHB. Therefore, the aim of this review was to focus on the methods of fruit waste pre-processing and the effect of fermentation variables on PHB production using fruit waste as a substrate. The relevant research findings on the use of different microorganisms, PHB production conditions and fruit waste-based substrates are also covered. Analysis of various studies revealed that pineapple and mixed fruit waste are effective for PHB production.

Critical overview of biomass feedstocks as sustainable substrates for the production of polyhydroxybutyrate (PHB)

Polyhydroxybutyrates (PHBs) are a class of biopolymers produced by different microbial species and are biodegradable and biocompatible in nature as opposed to petrochemically derived plastics. PHBs have advanced applications in medical sector, packaging industries, nanotechnology and agriculture, among others. PHB is produced using various feedstocks such as glycerol, dairy wastes, agro-industrial wastes, food industry waste and sugars. Current focus on PHB research has been primarily on reducing the cost of production and, on downstream processing to isolate PHB from cells. Recent advancements to improve the productivity and quality of PHB include genetic modification of producer strain and modification of PHB by blending to develop desirable properties suited to diversified applications. Selection of feedstock plays a critical role in determining the economic feasibility and sustainability of the process. This review provides a bird's eye view of the suitability of different waste resources for producing polyhydroxybutyrate; providing state-of the art information and analysis.

Yellow mombin and jackfruit seeds residues applied in the production of reducing sugars by a crude multi-enzymatic extract produced by Penicillium roqueforti ATCC 101110

BACKGROUND

As an alternative to the use of widely investigated agro-industrial residues, the present study aimed to promote the valorization of two selected residues, yellow mombin seed (YS) and jackfruit seed (JS), as a result of their enhanced performance.

RESULTS

YS was applied as a solid state substrate for Penicillium roqueforti ATCC 101110 cultivation (25 °C, A_w = 0.963, 10⁷ spores g^-1 and 142 h) to produce a crude multi-enzymatic extract (CE-YS) containing activities of CMCase = 31.95 U g^-1 , xylanase = 56.85 U g^-1 , exoglucanase = 5.55 U g^-1 and FPase = 24.60 U g^-1 . CE-YS was then applied to six different residues saccharification and the best performance was obtained with jackfruit seed residue (JS), which was selected for enzymatic saccharification. The highest productivity of reducing sugars expressed as glucose (6.26 mg g^-1 h^-1 ) was obtained under the conditions: 40.7 g L^-1 JS, 5 mmol L^-1 MgCl₂ , 65 °C, 120 rpm, pH 3.0 (citrate buffer 50 mmol L^-1 ) and 18 h.

CONCLUSION

The residues, YS and JS, can be used satisfactorily for the production of bioproducts of great industrial applicability, such as crude extracts (containing cellulolytic enzymes) and RS (which can be converted, for example, into bioethanol). © 2020 Society of Chemical Industry.

Effect of Indian brown seaweed Sargassum wightii as a functional ingredient on the phytochemical content and antioxidant activity of coffee beverage

Seaweed is a novel food source that is packed with bioactive compounds but is rarely used in its raw/cooked form. An efficient nutrient delivery medium is required to make the potential health benefits of seaweeds accessible to the general population while maintaining its palatability. In this study, coffee infused with different seaweed concentrations (1%, 3%, 5%) were prepared and their physico-chemical, phenolics, flavonoids, antioxidants, rheology, thermal and spectral characteristics were observed. Increase in seaweed concentration resulted in increased acidity and decreased total soluble solids of the beverage with no distinct color change. Rheological measurements showed flow behavior index in the range of 1.09-1.34 indicating dilatant tendency of the seaweed-coffee infusions which gradually decreased towards a Newtonian nature with increase in seaweed concentration. Higher detection of flavonoids and ferric reducing antioxidant power was possible with increase in seaweed concentration from 1 to 5%. However, no significant changes in total phenols and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity was observed. Sensory evaluation of the coffee drinks was done using fuzzy logic which showed highest sensory acceptability for the infusion with 1% seaweed concentration. Thermograms showed changes in flavor profile on increasing seaweed concentration which was later confirmed using Fourier transform-infrared spectroscopy. Results of the study highlight that coffee can be successfully used to mask the off-flavor of seaweed while disseminating its health benefits to the general population through an effective and extensively utilized food medium.