Food Biophysics最新文献

Chickpea flour, known for its protein richness, takes centre stage in this research, where innovation meets nutrition. Our findings illuminate a remarkable enhancement in protein content, with hydrodynamic cavitation treatment leading to a substantial increase. Notably, the 60-minute treatment (S2) and 90-minute treatment (S3) samples display an initial viscosity alteration compared to the control (S1), hinting at exciting possibilities for culinary applications. Furthermore, we delve into protein and starch digestibility, unveiling intriguing results. Protein digestibility reveals that S2 and S3 exhibit modified amino acid content, suggesting an impact on protein metabolism. Simultaneously, starch digestibility analysis indicates that S2 showcases improved digestibility, while S3 presents a unique perspective by displaying reduced starch digestibility. Our exploration extends to the glycaemic index, with S2 exhibiting a heightened index in comparison to both S1 and S3.

To evaluate the storage stability of flours from Rhynchophorus phoenicis and Imbrasia truncata larvae obtained by freeze-drying, their moisture adsorption isotherms have been determined at 20, 30 and 40 °C and their thermal properties explored by differential scanning calorimetry (DSC). DSC evidenced reversible transitions attributed to lipid melting/crystallization between − 60 and 90 °C. The GAB model was chosen to model adsorption isotherms. It evidenced 2 and 3 water compartments in R. phoenicis and I. truncata flours, respectively. Adsorption isotherm of R. phoenicis is type III at 20 and 30 °C, while that of I. truncata is type II at 20, 30 and 40 °C. GAB model also allowed calculating flour monolayer moisture contents (Mo ≤ 5.6 g/100 g dry matter (DM)). Net isosteric heat (qst) was evaluated. q_st decreases with increase of water content and was higher for the flour of I. truncata larvae (from 8571 to 503 J/mol; 2,5 to 20 g/100 g DM) than that of R. phoenicis larvae (from 1750 to 124 J/mol; 5 to 30 g/100 g DM). Finally, the maximum storage times of the insect flours under typical packaging and storage conditions were estimated according to the Heiss and Eichner model. Highest for the flour of I. truncata, q_st remained however moderate indicating that the insects can be dried without important energy supply. The estimated storage time of R. phoenicis larvae and I. truncata flours (3 g/100 g DM), stored at 20 °C in polyethylene bags, could reach 263 (8 months and 19 days) and 116 days (3 months and 24 days), respectively. These results provide valuable insights into the stability and potential applications insect flour in the food processing industry. This information could help in determining suitable packaging methods and storage conditions to maintain the quality and shelf life of products containing these flours to set safety and quality standards for such products.

Washing is a key process in surimi processing, whereby lipids, water-soluble proteins, pigments, and other factors that impede gel formation are separated from the fish. However, this process significantly reduces the meat yield of raw fish and destroys its nutrients, generating more organic wastewater. To enhance the process efficiency, ultrasound is used to assist washing process. This study aims to investigate the effects of ultrasound-assisted washing at different power levels (0 W, 150 W, 250 W, 350 W, and 450 W) on the quality, biochemical characteristics, protein conformation and gel-forming ability of surimi from silver carp. The results showed that ultrasound-assisted washing could increase yield by over 4% and reduce crude fat content by approximately 0.5% than control group. Protein secondary structure indicated that ultrasonic treatment of 250 W didn’t cause significant loss of α-helix. Moreover, the gel strength of 450 W group was roughly 17% more than that in control group. 250 W ultrasound-assisted washing was the most effective and significantly improved the productivity and quality of surimi.

Ergosterol possesses a variety of physiological activities, however, its application is limited due to its poor water solubility and photosensitivity. In this study, by using the ultrasonic-assisted heating method, recombinant human H-ferritin (rHuHF)–ergosterol nanocomposites (FEs) were designed, and after the characterization, the light stability, serum stability, sustained release character, and cholesterol-lowering property in vitro were analyzed. The results showed that FEs maintained a spherical morphology with the same particle size as rHuHF. About 17 ergosterol molecules were successfully encapsulated in one ferritin molecule with an encapsulation rate of (27.28 ± 0.29)% and a drug loading of (1.63 ± 0.02)%. The light stability of FEs was increased compared with free ergosterol molecules. The FEs also exhibited good serum stability. The results of simulated gastrointestinal digestion indicated that the rHuHF cage was able to prolong the release of ergosterols. FEs digesta can reduce the solubility of cholesterol in micelles. Additionally, molecular docking displayed that ergosterol can competitively inhibit cholesterol binding to human Niemann-Pick C1-Like 1 (NPC1L1), which might play an important role in preventing the delivery of cholesterol to the membrane for accumulation. This work offers an approach to encapsulate and deliver ergosterol depending on the advantage of ferritin nanocage, which has the potential to be applied in food industry.

Abstract

Zingiber cassumunar Roxb. rhizome extract has high potential as an antimicrobial agent, which can be applied in various food production processes and plays role in inhibiting various foodborne pathogenic microorganisms. The purpose of this research was to study the mechanism and stability of the extract’s antimicrobial activity, especially when observed from the degradation of microbial cells. Specimens were extracted by maceration method with three types of solvents with different polarities and steam distillation. The 25% extract using ethyl acetate solvent showed antimicrobial activity against Gram-negative bacteria (Enterobacter spp. and Pseudomonas spp.); Gram-positive bacteria (Listeria monocytogenes); and fungi (Rhizopus oryzae and Penicillium spp.) in well-diffusion assays. The antimicrobial activity of the extract was lower than several commercially used antibiotics such as antibacterial (penicillin G and streptomycin) and antifungal (nystatin) but exhibited broad inhibition spectrum against pathogen samples. The antimicrobial activity of the extract will increase at a low pH condition (pH 4–5) and is stable in 1–4% salt solution. Although the inhibitory activity was decreased slightly upon heating, the antimicrobial activity was stable up to 15 min of exposure to high temperatures (80^○C and 100^○C). Antimicrobial activity of the extract was reported to be higher in a spheroplast and protoplast condition. Leakage of metal ions such as calcium and potassium ions indicated that the activity of the extract could interfere with cell permeability so that the cells become lysed. The extract caused some damage to the bacteria and fungi cell bodies such as holes, curls, shrinkage, elongation, and swelling.

Abstract

The interaction between a low molecular weight (i.e., 19 kDa) ethyl cellulose (EC) and a commercial monoglyceride (MGc) in the development of EC-MGc oleogels was evaluated through rheological, DSC, and infrared spectroscopy measurements. The oleogels were developed through cooling (80°C to 2°C, 10°C/min) vegetal oil solutions of EC at concentrations above (10%), below (7%), and at EC’s minimal gelling concentration (8%), and in EC-MGc mixtures using MGc below its minimal gelling concentration (0%, 0.1%, 0.25%, 0.5%, 1%). At 0.10% MGc most of the monoglycerides developed hydrogen bonds with the EC developing oleogels structured through EC-monoglyceride-EC interactions. As the EC concentration increased the EC-0.1% MGc oleogels achieved higher elasticity (G’) than the EC oleogels. Using MGc concentrations ≥ 0.25% the excess of monoglyceride increased the oil’s relative polarity favoring the EC-EC over the EC-monoglyceride-EC interactions. Below 10 °C the monoglycerides in the oil crystallized within the free spaces of the entangled EC fibers acting as active filler. Thus, at the same EC concentration the EC-0.25% MGc, EC-0.50% MGc, and EC-1% MGc oleogels achieved higher G’ than the corresponding EC-0.10% MGc oleogels (P < 0.01). This behavior was more evident as the EC concentration increased. The rheological measurements during cooling showed that below 40 °C the EC went through a structural rearrangement that decreased the oleogels’ elasticity. Since the structural rearrangement was cooling rate, EC and MGc concentration dependent, these factors could be used to tailor the rheological properties of oleogels developed with low molecular weight EC.

Tea egg is a Chinese traditional snack and leisure food, fresh chicken eggs and tea are the main ingredients. The influence of tea is the most important one, because the polyphenols in different teas can affect the egg white gel (EGL) and will impact the quality and flavour of tea eggs. To investigate the effects of tea on the physicochemical characteristics of EGL during tea egg making, the common used tea (green and black tea), and their usual physical form (in leaf and powder) were selected, respectively. The results indicated that the physicochemical characteristics of EGL were more susceptible to green tea than black tea. EGL also had different results on the physical form of tea. When the tea concentration ranged from 1 to 12 g/100 mL (per gram dry tea in 100 mL of water), the soluble protein content and surface hydrophobicity in the EGL were both direct proportional to the tea concentration, whereas the pH exhibited an inverse relationship. The water holding capacity in green tea groups was like an inverted “U”, but it was kept increased in black tea groups. The content of free sulfhydryl groups in tea leaf groups was like an asymmetric inverted “V”, but it was positive correlation with the amount of tea in powder groups. Considering only the physicochemical properties of protein gel in egg white, green tea in leaf form of 6 g/100mL could make eggs with the best gel quality and stronger tea flavour. This study will standardize tea eggs making, and promote the sharing of traditional Chinese cuisine with the global community.