Food Biophysics最新文献

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.

Abstract

Pectin was isolated from the African star apple (ASA) (Chrysophyllum albidum) fruit at a fully ripe stage from two geographical zones in Ghana. The study employed Box-Behnken design to determine the effects of extraction conditions, time (30–90 min), temperature (70-90^oC), and pH (2.5–3.5) on yield, degree of esterification and uronic acid content of the pectin extracts. The optimal conditions of the design (90^oC for 60 min at a pH of 2.5) predicted a yield of ~ 11%, with a degree of esterification of 65% and uronic acid content of 75%, which were similar to the experimental values of yield (8.5–10.6%), degree of esterification (DE) (66.8–67.1%) and uronic acid (UA) content (74.5–76.2%). The ASA pectin extracted were characterized in comparison with commercial citrus pectin based on their physicochemical properties. The emulsification capacity of the pectin revealed higher emulsion stability, closely related to commercial citrus pectin. FT-IR analysis of the pectin revealed the presence of a polygalacturonic acid in both samples. The study confirmed that commercial citrus pectin and the citric acid extracted pectin from ASA had comparable characteristics and could be utilized as an alternative extraction source.

Abstract

Aflatoxins (AFs) are toxic secondary metabolites of filamentous fungi which can reduce the quality of several food commodities like hazelnut and hazelnut products. For the AFs, the data were fitted to polynomial response models using multiple regression analysis, resulting in high coefficients of determination (R² values ranging from 0.8917 to 0.9674) for each type of aflatoxins. The optimal conditions for achieving maximum degradation percentages for total aflatoxins (AFT) and AFB1 were determined to be US power of 80W, enzyme treatment of 2.5 U g sample, and 20 min of US application for 12.5 µg kg AFT conditions after graphical and numerical optimizations. The optimum conditions resulted in 44.33% and 45.58% degradation for AFT% and AFB1 respectively, with predicted values of 43.93% and 44.17% for AFT% and AFB1. The data exhibited that, enzyme treatments were not significant for degradation for AFB1% and AFT%, whereas significant for AFB2 and AFG2. Depending on the initial AFT concentration, more than 50% degradation rate was achieved by current design parameters. Study results indicated that US treatment can alter certain quality parameters of hazelnut paste, including changes in aroma, a decrease in browning index, and a slight increase in peroxide value.

In this study, kefir-containing healthy snacks were produced by using 3D food printing technique. Although kefir has many important health benefits, its consumption is quite low. It was thought that kefir-containing snacks in attractive shapes produced with a 3D food printer could increase the kefir consumption. For this purpose, disintegrated kefir gels prepared with starch, gelatin and alginate were used as inks. First, the minimum gelation concentration (C*) of each gelator was determined. Then, disintegrated gels with concentrations of C*, C*+1%, and C*+2% were prepared with each gelator and the effect of gelator concentration on printing quality was investigated for each gelator. Printing quality was associated with storage modulus, loss factor and flow behavior, and the minimum gelator concentration required for a suitable formulation for 3D printing (highest printability and dimensional stability) was determined as 5%, 6% and 3% for starch, gelatin and alginate, respectively. Lactobacillus spp. and Lactococcus spp. contents of the starch-based sample were found to be significantly lower than those of fresh kefir and gelatin and alginate-based samples. Sensory properties and consumer appreciation were lower for the gelatin-based sample. Due to the high printing quality (98% printability and 99% dimensional stability), high probiotic content (7.81 and 8.13 log cfu/ml Lactobacillus spp. and Lactococcus spp. content, respectively) and high consumer appreciation (4.71 out of 5 for general acceptance), alginate-based sample (containing 3% alginate) was chosen as the best sample. In conclusion, new, chewable, alive, alternative kefir products were successfully developed for consumers seeking new ways of kefir consumption.

In this study, microalgae proteins (Spirulina and Chlorella) were extracted, characterized, and investigated for their potential techno-functionalities. The proteins from the microalgae biomass were extracted by alkaline solubilization followed by iso-electric precipitation. Subsequently, their physicochemical characteristics (microstructure, thermal stability, secondary structure, and crystallinity) and functional properties (protein solubility, water and oil holding capacities, as well as emulsifying and foaming properties) were investigated. Spirulina biomass resulted in a high extraction yield (37%), giving a protein isolate containing 90% of proteins. Both Spirulina and Chlorella protein extracts displayed high thermal stability. FTIR analysis revealed a clear difference in the secondary structure of the protein extracts. A slight difference in microstructure was noted between the two proteins, but both had small particle sizes and uniform dispersity. Spirulina proteins were more crystalline (53%) than the Chlorella proteins (36%). Spirulina showed better functional properties (protein solubility, emulsifying, and foaming properties) compared to Chlorella. We observed that the Spirulina protein had more water-holding capacity than the Chlorella protein, while the latter also showed appreciable oil-holding capacity. These findings suggest that the microalgal proteins could be useful in the food industry.

In this study, we successfully fabricated vanillin (VAN) incorporated poly (ethylene oxide) (PEO) and whey protein isolate (WPI) nanofibers and optimized the preparation conditions. The nanofibers were prepared at different percentages of PEO/WPI/VAN, and the characterization techniques of XRD, FTIR, FESEM, and DSC were employed to analyze the samples. Additionally, mechanical properties, and physicochemical were measured to identify the critical factors for nanofiber optimization. The best parameters observed at a PEO 10%: WPI 3% ratio of 80:20, producing narrower and smoother fibers (average diameter of 264.07 nm; additionally, the addition of VAN to the optimal PEO/WPI ratio (80:20) decreased fiber diameter. Furthermore, vanillin was incorporated into the optimized PEO/WPI nanofibers at concentrations of 1MIC (10 mg/mL) and 2MIC (20 mg/mL) to evaluate their antioxidant and antibacterial abilities before and after electrospinning. In summery, these findings suggest that the PEO/WPI nanofibers, with the addition of VAN, hold potential as a promising platform for future applications in the food and drug industries. Further research can build upon these findings to explore the specific functionalities and applications of these nanofibers in greater detail.