Journal of Food Science最新文献

In this study, a series of characterizations and analyses of fibrous β-lactoglobulin self-assembly (FBS) and worm-like β-lactoglobulin self-assembly (WBS) were carried out to investigate the key factors for the formation of self-assemblies of β-lactoglobulin under two different induced conditions. Compared with natural β-lactoglobulin, FBS was always positively charged, increasing to 9.69 mV when heated for 10 h, whereas WBS was always negatively charged, decreasing to −20.73 mV when heated for 20 min. Electrostatic interactions play a crucial role in the formation of both FBS and WBS. The free sulfhydryl content decreased by 10.4% at 20 min of heating compared with that at 1 min of heating. β-Lactoglobulin converted the exposed free sulfhydryl groups to disulfide bonds when heated under neutral conditions, and disulfide bonds played a key role in the formation of WBS. The surface hydrophobicity of FBS reached its maximum at 1 h of heating, while that of WBS reached its maximum at 15 min of heating. The hydrophobic interactions played an extremely important role in the formation of the two self-assemblies. The investigation of the formation mechanism of FBS and WBS is of great significance for the preparation of β-lactoglobulin self-assembled gels.

Practical Application

Probing the formation mechanism of β-lactoglobulin self-assemblies provides new methods and ideas for the preparation of β-lactoglobulin gels, which is important for improving the structure and properties of gel carriers prepared from bio-based materials.

As a premium-grade oil, Sesamum indicum L. oil is characterized by polyphenols and lignans. However, the influence of oil extraction methods (OEMs) on sesame oil's active ingredients and antioxidant activities lacks sufficient research. Herein, sesame oils were prepared with five OEMs, and their active ingredients and antioxidant activities were systematically investigated. The results demonstrated that the antioxidant activities of sesame oil extracts varied significantly among OEMs, and the ethanol extract of solvent extraction-ethanol (SEE) sesame oils possessed the highest inhibition rates of DPPH⁻ (2,2′-diphenyl-1-picrylhydrazyl radical; 67.07 ± 0.78%) and ABTS⁺ (2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt; 18.64 ± 1.34%), and the highest antioxidant ability to H₂O₂-induced HepG2 cells. Meanwhile, the highest total phenolic content (TPC) was found in SEE oil (152.96 ± 5.35 mg/kg). UPLC-QTOF-MS/MS illustrated that 52 ingredients were verified in sesame oils, including nine lignans, 33 phenols, and 10 non-phenols. Furthermore, high performance liquid chromatography (HPLC) presented that the content of phenol and lignan profiles varied significantly among OEMs, while the compositions remained unchanged. Besides, the correlation analysis revealed that 14 active ingredients exhibited a positive correlation with antioxidant activities. Among them, ethyl vanillate, (+)-justiciresinol, pinoresinol, kaempferol 3-O-[2-O-(trans-p-coumaroyl)-3-O-α-L-rhamnopyranosyl]-β-D-glucopyranoside (KTCRG), cistanoside F, and sesamolinol showed significant positive correlation with antioxidant activities (p < 0.05). It was believed that KTCRG, a glycosylated kaempferol, was responsible for the high antioxidant activities of sesame oils. Our results provided a viewpoint on OEMs for the quality of sesame oils.

Practical Application

In the subsequent extraction of sesame oil, specific ingredients can be more selectively retained and enriched to improve the acquisition of high-quality sesame oil and promote the quality grading of sesame oil. Meanwhile, the results of this study also have certain research value for the high-quality extraction of other vegetable oils.

Ultrasound (US) has gained significant interest in the food industry, and its incorporation in block freeze concentration (BFC) for the separation step could be interesting due to the ability to extract and preserve bioactive compounds. This study aimed to investigate the use of the US method as a novel assisted technique in the block freeze concentration (US-BFC) process applied to peppermint infusion (Mentha piperita L.). Freezing procedures were performed at −20°C for 12 h, and the frozen samples were then transferred to an ultrasonic bath. Different US frequencies and durations were evaluated in the separation step. Concentration efficiency, concentration index, and solute yield were determined to identify the best conditions in terms of process parameters at three multi-stage cycles, focusing on physicochemical analysis, bioactive components, antioxidant capacity, and antibacterial assay of the concentrated phase. A frequency of 100 kHz and a duration of 3 min presented the highest efficiency (78.2%–56.0%), concentration index (4.1–38.6), and solute yield (0.4–0.1 kg concentrated solute/kg initial solutes). From cycle to cycle, US-BFC significantly increased the solutes as well as the total and individual bioactive content, confirming an increase in antioxidant capacity. Moreover, the concentrate fraction from the last cycle confirmed an antibacterial effect against Staphylococcus aureus and Listeria monocytogenes, achieving a minimum inhibitory concentration (MIC) of 29.9 and 5.5 µg/mL, respectively. The present findings signified that US-BFC can positively enhance the separation and concentration of peppermint infusion, without compromising its quality and nutritional properties.

Practical Application

This study shows that ultrasound can be coupled with block freeze concentration, and the combination serves an operative concentration/separation technology to increase a considerable amount of solutes without degrading the thermosensitive compounds of the concentrates. We expect that ultrasound-assisted block freeze concentration can be applied to other liquid foods, and thus, the concentrates can be used in the food, cosmetic, and/or pharmaceutical industries.

The use of blue light within a range of 400–470 nm holds significant potential for sanitization purposes. However, due to an extended exposure duration needed for an antibacterial effect, the utilization of a photosensitizer (PS) to increase the efficacy of the treatment becomes essential. This study investigated prospective use of onion peel extract as a PS in combination with 405 nm blue light for the inactivation of Salmonella Typhimurium, a common foodborne pathogen on eggs. Extracts were obtained using 99% ethanol, 50% ethanol, and distilled water (DW). Their photosensitizing activities were then compared. The combination of 405 nm blue light and onion peel extract using 99% ethanol reduced bacterial populations more effectively than blue light treatment alone, while also increasing reactive oxygen species generation, cell membrane permeability, lipid peroxidation, and DNA damage levels. However, the antimicrobial effect of the 99% ethanol extract did not show a concentration dependence. Spraying DW extract on eggshell treated with 99% ethanol onion peel extract at 1 mg/mL and blue light further enhanced Salmonella reduction. Liquid chromatography was conducted for component separation. However, none of the separated fractions exhibited a significant antibacterial effect, suggesting that the active compounds responsible for antibacterial activity might work synergistically in the crude extract rather than individually. In contrast, the crude extract exhibited a significant antibacterial effect, suggesting that 99% ethanol-extracted onion peel can serve as a PS, particularly in its crude state without purification, and effectively inactivate Salmonella on eggshells.

Practical Application

Antimicrobial blue light (aBL) in the range of 400–470 nm is a promising nonthermal technology with several advantages, including minimal impact on food quality and safety. This study optimized the concentration of onion peel extract to improve its effectiveness as a photosensitizer in aBL treatment against Salmonella Typhimurium on eggshells. These results may serve as a reference for further optimizing aBL treatments, offering a potentially sustainable and cost-effective photosensitizer for pathogen control.

The present study focuses on the shelf-life extension of partially baked rolls using modified atmosphere packaging in combination with oxygen scavenging technology. The strategy used was to isolate and identify molds from a bakery environment and to test the effect of CO₂ on their growth. In vitro testing was performed as a preselection for mold strains that are able to grow under 80% CO₂, after which the growth on partially baked rolls was investigated. It was found that strains of Penicillium are more resilient to high CO₂ concentrations, compared to Aspergillus strains, both in vitro and on partially baked rolls. Growth of P. crustosum SB20 and P. paneum SB14; and A. clavatus SB03 and A. oryzae SB02 on partially baked rolls was delayed by 7 and 14 days, respectively, under 80% CO₂ and 20% O₂ compared to normal atmosphere. The delay in growth of A. clavatus SB03 could further be extended by 2–3 days, with an oxygen concentration reduced to 1%; however, a reduction to 0.5% oxygen no longer made a difference. The growth of P. paneum SB14 was not influenced by the reduction of oxygen. The only condition under which both strains were not able to grow within a period of 61 days was under 80% CO₂ and 20% N₂, with an oxygen absorber inside the packaging. The study demonstrated that to effectively examine the impact of modified atmosphere on the mold-free shelf-life of bakery products, it is crucial to select and conduct tests using mold species from the production environment.

Practical Application

The influence of CO₂ on the growth and sporulation of mold varies depending on the tested strain and species. To analyze the effects of packaging conditions (modified atmosphere packaging or O₂ scavengers) on the mold-free shelf-life of bakery products/food products, it is essential to utilize molds that have been isolated from either the product being tested or the manufacturing environment.

To enhance the shelf life of fresh-cut bitter bamboo shoots (Pleioblastus amarus), this study developed three distinct solutions: selenium nanoparticles (SeNPs), polysaccharide-modified selenium nanoparticles (SeNPs-sa), and sodium alginate-polysaccharide-modified selenium nanoparticles (SA&SeNPs-sa). The solutions were characterized, and their antioxidant activities were compared to identify the most stable and effective formulation for preserving fresh-cut bitter bamboo shoots. The results revealed that the synthesized selenium nanoparticles were spherical, with an average diameter of 86.96 nm and a ζ-potential of −3.81 mV. Ultraviolet spectroscopy and energy spectrum analysis confirmed their identity as SeNPs. Upon interaction with sodium alginate (SA), the average particle sizes of SeNPs-sa and SA&SeNPs-sa increased to 91.07 and 120.43 nm, respectively, with ζ-potentials of −18.27 mV and −39.43 mV. The shift in the absorption peaks observed in the infrared analysis further indicates that the stability of SA&SeNPs-sa is greater than that of SeNPs and SeNPs-sa. Regarding antioxidant activity, SA&SeNPs-sa exhibited superior 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ABTS⁺ radical scavenging rates of 57.91% and 55.80%, respectively, significantly outperforming SeNPs and SeNPs-sa. Subsequent experiments evaluated the preservation effects of SA and SA&SeNPs-sa on fresh-cut bitter bamboo shoots. Compared to the control and SAtreated groups, SA&SeNPs-sa effectively delayed yellowing by inhibiting polyphenol oxidase and peroxidase activities, while maintaining higher catalase activity and total phenolic content. Furthermore, this treatment significantly reduced weight loss and respiratory intensity, slowed the degradation of soluble proteins and total sugars, and inhibited microbial proliferation on the surface. In conclusion, the SA&SeNPs-sa treatment effectively mitigated quality deterioration and significantly extended the shelf life of fresh-cut bitter bamboo shoots.

Practical Application

The deterioration of fruits and vegetables after cutting causes a decrease in economic value. In this study, composite coatings were fabricated by using sodium alginate as a film-forming matrix and adding selenium nanoparticles to extend the shelf life of fresh-cut bitter bamboo shoots. These coatings are easy to produce and apply and provide a sustainable solution to reduce waste of fresh-cut fruits and vegetables.