Food and Bioprocess Technology最新文献

Dried vegetable products serve as nutritional supplements in various culinary, pharmacological, and cosmetic applications. Heat is generally employed as a drying agent in traditional thermal drying methods. This involves a high energy cost and significantly reduces the nutritional quality of vegetable products. This study investigates an unconventional, non-thermal drying method for pomegranate arils (PA). It is based on the use of selective molecular sieves for water molecules. This merely permits the extraction of water without compromising the other components that the fruit still contains. Compared to other dehydration techniques, this drying method uses less energy. It consumes 6.5 kWh of energy to take out 1 l of water including energy consumption for the regeneration of molecular sieves, whereas lyophilization and thermal drying procedures require 19.5 kWh and 8 kWh of energy to remove 1 l of water, respectively. Despite that, there is a lack of previous research on drying pomegranate arils using molecular sieves. Drying process studies were conducted on several characteristics, including water activity, water content, color, hardness, and size variation. It has been also investigated how pretreatments such as freezing and osmotic dehydration enhance drying. Using freezing pretreatment, the time of the drying process was reduced from 34 to 10 h, resulting in a final normalized water content (NWC) of 22.23 ± 0.75%. According to the osmotic dehydration pretreatment (OD), water lost (WL) and solid gain (SG) stabilized with values of 42.38% and 0.38% after 300 min of drying. A drying kinetic modeling study was carried out. The Midilli et al. model describes the experimental results of pomegranate arils after non-thermal drying, which have the highest R² value (0.999) and lowest RMSE (0.0060) and χ² (0.00004).

Addressing the issue of unclear spectral evolution mechanisms in the early stages of fruit damage, which leads to lower accuracy and robustness of damage detection models, this study collected time-series data on browning-related color parameters, chlorophyll content, water content, and temperature differences during the early stages (0, 6, 12, …, 114, 120 min) of bruise development due to mechanical damage in 'Red Delicious' apples. By combining the spectral feature information of each sensitive band and using the method of transfer entropy, the study analyzed the information flow between physiological and biochemical indicators and spectral characteristics, unveiling the mechanism behind the spectral feature evolution in damaged apple areas. The conclusions are as follows: (1) The evolution of spectral characteristics within the 650–734 nm band is related to browning and chlorophyll degradation processes in the damaged areas, while the evolution of spectral characteristics within the 850–970 nm band is related to changes in the water content of the damaged areas. Additionally, the evolution of spectral characteristics within the 1255–1314 nm band is related to temperature changes in the damaged areas. (2) The effectiveness of different spectral characteristics in characterizing the extent of damage varies. From the perspective of the average transfer entropy value (overline{T }) and the maximum entropy value TE_max, the spectral characteristic tanθ has a significant advantage. In terms of the time dimension, the spectral characteristic tanθ has an advantage in characterizing damage in the early stages of apple damage (0–60 min), while the spectral characteristic (overline{R }) is more suitable after 60–90 min of damage. (3) Using the significance coefficient constructed from transfer entropy as an indicator and analyzing from the perspective of information transfer, the color parameters related to browning in the flesh area and the degradation of chlorophyll in the peel area are the main driving factors for spectral curve changes. Through the study of the spectral feature evolution mechanism after 'Red Delicious' apples bruising, this research provides insights and a theoretical basis for more reliably detecting minor early damage in apples.

Using nanoparticles or adsorption carriers to load actives substance instead of direct adding into the packaging films can slow down its release. In this study, halloysite nanotubes (HNTs) with acid etching treatment were used as an adsorption carrier to load oregano essential oil (OEO). The polylactic acid (PLA) film containing acid-etched HNTs loaded with OEO (consisting 2.5% acid-etched HNTs and 5% OEO) was prepared through melt extrusion casting method. The loading capacity of OEO in HNTs increased from 6.8 to 23.2% after acid etching treatment. The addition of acid-etched HNTs promoted the dispersion of OEO in the PLA matrix. The Fourier transform infrared spectroscopy showed the interactions among OEO, acid-etched HNTs, and PLA via hydrogen bonds. The PLA films added with OEO or acid-etched HNTs loaded with OEO both exhibited excellent anti-ultraviolet property. Compared with the PLA film containing OEO only, the film containing OEO and acid-etched HNTs exhibited lower tensile strength and elongation at break, achieved slower release of OEO in food simulant (10% ethanol), and showed lower antibacterial activity, which was closely related to their release behavior. However, there were no significant differences in oxygen and water vapor permeability between these two films. In addition, the application of these films on spinach packaging stored at 4 °C for 15 days were studied. The results showed that the film containing OEO and acid-etched HNTs exhibited the best maintenance for spinach quality by inhibiting its respiration rate, weight loss, browning, and microbial growth. It might be related to the gas permeability of the film and the release behavior of OEO from film. This study offered a great potential to develop controlled release PLA active films for vegetable packaging through melt extrusion method.

This study investigated the antibacterial capacity and mechanism of surfactin (prepared by fermenting soybean meal with Bacillus subtilis SOPC5) against Staphylococcus aureus by examining its influences on the bacterial morphology, cell wall and membrane, as well as metabolic activity. The efficiency of surfactin in pork preservation was also investigated. HPLC-MS analysis showed that surfactin’s purity reached 97.4%, containing five congeners. The minimal inhibition concentration (MIC) and minimal bactericidal concentration (MBC) of surfactin against S. aureus were 1.6 and 3.2 mg/mL, respectively. The result of scanning electron microscopy observation revealed that 4 h of surfactin exposure resulted in deformation and even collapse of S. aureus. AKP assay, membrane potential analysis, extracellular protein and nucleic acid content measurement, and PI staining intensity assay showed that surfactin destroyed the cell wall and cell membrane of S. aureus. Decreases in iodonitrotetrazolium chloride levels and ATP enzyme activity indicated that surfactin could inhibit the metabolic ability of S. aureus. Furthermore, surfactin demonstrated an excellent antibacterial action on S. aureus within 5 days of pork storage without changing its texture. These findings suggest that sufactin has a great application potential in pork preservation.

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Innovative electrospun pullulan/hemp protein isolate nanofibers (PUL/HP) with lecithin were successfully formulated for the delivery of phenylethanoid glycosides (PGs) from Teucrium montanum extract, at PUL to HP ratios of 80:20, 70:30, 60:40, 50:50, 40:60, and 30:70, based on total polymer mass (w/w). A higher HP content led to a more elastic behavior, which was stimulated by a stronger entanglement between polymer and polypeptide chains. The biopolymers used showed favorable compatibility with the investigated PGs, achieving an encapsulation efficiency of over 80 %. The increased elastic behavior led to the formation of a bead-on-string morphology and a higher average diameter. The thermal stability of the loaded nanofibers was diminished by the presence of incorporated polyphenolic extract. Under simulated gastrointestinal conditions, a sustained release of total phenolic content from the delivery systems was achieved. According to the FTIR spectra, this is mainly due to the efficient interplay of hydrogen and hydrophobic interactions with the polyphenols within the polysaccharide-phospholipid-polypeptide structure. The circular dichroism spectra showed that the polyphenol extract was involved in the secondary HP structure, resulting in a rather random, uncoiled structure. These results provide a time- and cost-efficient approach to stabilize naturally immiscible biopolymers without crosslinking or emulsion preparation, while similarly altering the physicochemical properties of the drug delivery systems.

Due to the increasing need to develop sustainable options for food packaging, a composite material (PLA-CHI) produced by blending poly(lactic acid), maleic anhydride-grafted polypropylene, oxidized polypropylene, and chitosan was challenged against Escherichia coli and Listeria innocua in apple juice, alone or in the combination with two physical hurdles: ultraviolet light (UV-A light) or mild heat (50 °C). PLA-CHI was more effective against L. innocua, being able to reduce its population by up to > 99.998% under UV-A exposure or mild heat. In contrast, E. coli exhibited more resistance against PLA-CHI and either hurdle, with its population declining by up to 99.8% under UV-A light exposure and by up to 99.99% under mild heat. Surface analyses, including infrared spectroscopy and atomic force microscopy, confirmed the overall physical and chemical stability of PLA-CHI after exposure to the physical hurdles. This study confirms the effectiveness and synergy between antimicrobial packaging and hurdle technology.

In this study, the gamma-cyclodextrin (γCD) inclusion complexes with essential oil (EO) compounds linalool and geraniol were encapsulated in pullulan nanofibers using an electrospinning technique. The nanofibers were produced with the initial EO content of ~ 11% (w/w) and ~ 74 to 77% of these volatile compounds could be preserved in pullulan/EO-γCD nanofibers due to inclusion complexation. On the other hand, only ~ 15 to 23% of EO could be kept in the case of pullulan/EO nanofibers in the absence of γCD. The EO-γCD inclusion complexation also ensured improved thermal stability for EO compounds, and their volatilization shifted from ~ 119–139 to ~ 239–292 °C ranges for pullulan/EO-γCD nanofibers. Moreover, pullulan/EO-γCD nanofibers displayed substantial long-term storage stability and, ~ 48 to 64% of EO content was still preserved even after 4 weeks, while this ratio was in the range of ~ 0.3 to 4.5% in the case of pullulan/EO nanofibers. The pullulan/geraniol-γCD nanofibers displayed an effective antibacterial activity against Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria, and overwhelmingly better performance compared to pullulan/geraniol nanofibers due to the inclusion complexation. Briefly, EO-incorporated nanofibers were generated using GRAS γCD molecules and an edible pullulan polymer, and this approach can be a promising alternative to be effectively used in the food industry for the encapsulation and delivery of volatile EO compounds.

The tiger nut (Cyperus esculentus L.) possesses a substantial nutrition yet its industrialization process is characterized by sluggishness. Herein, we introduced a green approach to achieve simultaneous extraction of oil and glucose syrup from tiger nuts via an amylolysis-assisted aqueous extraction process (AAEP). Briefly, tiger nut flour was rinsed with fivefold distilled water for 1 h to eliminate non-starch polysaccharides and separate the majority of the oil (64.02%). Subsequently, liquefaction was conducted using α-amylase (AMY), followed by saccharification employing amyloglucosidase (AMG) and pullulanase. The operating conditions of amylolysis were optimized which include enzyme dosage and time of liquefaction and saccharification. Eventually, the final yield of oil and glucose syrup reached 89.84% and 89.41%, respectively. Confocal laser scanning microscopy (CLSM) results demonstrated that starch hydrolysis promoted the release of encapsulated oil, which enhanced the extraction efficiency of oil. Overall, our findings highlight that AAEP is an effective industrial approach facilitating comprehensive utilization of tiger nuts.

Graphical Abstract

High-pressure processing (HPP) is a non-thermal preservation technology that can be applied as a control measure to inactivate pathogens and spoilage microorganisms once RTE meat products are packaged in a convenient format. HPP efficacy highly depends on product characteristics, but the impact of the sodium-reduced formulations and the effect of packaging atmosphere are scarcely known. The aim of the present work was to assess the effect of standard and sodium-reduced formulations from two different brands (A, B) under different packaging (vacuum and modified atmosphere packaging (MAP)) on the HPP inactivation kinetics of Listeria monocytogenes and spoilage lactic acid bacteria in cooked ham. Slices of cooked ham with standard and sodium-reduced formulations were inoculated with L. monocytogenes CTC1034 and Latilactobacillus sakei CTC746 (slime producer), packaged in vacuum and MAP (CO₂:N₂, 20:80), and pressurized (400 MPa/0–15 min) after 1 h (vacuum, MAP) or 24 h (MAP-exposed). Parameters of HPP inactivation kinetics were estimated by fitting the Weibull model to log reduction data. Results showed that the efficacy of HPP in sodium-reduced cooked hams tended to decrease compared to standard formulations, being the difference statistically significant for L. sakei. For L. monocytogenes, a significant enhancing effect of MAP was observed when HPP was applied just after packaging (1 h, MAP) of cooked ham of brand A. In the case of L. sakei, the inactivation by HPP was only enhanced in MAP-exposed samples. Therefore, the use of HPP as a control measure must be applied through a product-oriented approach considering the type of packaging and the time period between packaging and HPP.

Reducing fruit and vegetable waste at the household level would significantly contribute to decreasing the overall environmental impact of the food chain. Achieving this requires an understanding of the most critical factors in product quality to predict shelf life. Broccoli has been chosen to model this as it is consumed worldwide. To simulate consumer conditions, broccoli heads were purchased in bulk from a local supermarket and stored (in a disposable, compostable bag) at four storage temperatures (3, 5, 7, and 12 ºC) for 13 days. Broccoli quality was evaluated using five factors: weight loss, vitamin C content, total phenolic content, chlorophyll content, and consumer acceptability. Individual shelf-life estimates were calculated for each factor independently using kinetic models and adequate threshold values. The product’s shelf life was obtained by combining the individual estimates; consumer acceptability was noted as being the most relevant criterion at any temperature, followed by vitamin C content or weight loss depending on the storage temperature. However, the effect of temperature was nonlinear; variations within the 3–5 ºC range had little impact on shelf life (13–14 days), whereas an increase to 7 ºC would cause a significant reduction in shelf life (9 days). Hence, according to the fitted models, it is particularly important that the temperature of refrigerated broccoli is closely controlled within the range of 3 to 5 ºC. This information is highly relevant to the industry, supermarkets, and the end consumer, as it emphasizes that temperature control of broccoli is essential to ensure the quality of the product throughout its shelf life, helping to reduce food waste.