Effect of a sea buckthorn pomace extract-esterified potato starch film on the quality and spoilage bacteria of beef jerky sold in supermarket

Optimized extraction, enrichment, identification and hypoglycemic effects of triterpenoid acids from Hippophae rhamnoides L pomace

The Hippophae rhamnoides L. pomace was generated in the production process for juice, wine of food industry. To expand the application of pomace, the extraction process optimization, enrichment and identification of triterpene acids were performed in this study. The extraction yield was 14.87% under optimal ultrasound-assisted extraction techniques performed via response surface methodology. The extract was subsequently purified to obtain the triterpenoid acid enrichment fraction (TPF) with the content of 75.23% ± 1.45%. 13 triterpenoid acids were identified via UPLC-Triple-TOF MS/MS and further semi-quantified through comparison with triterpenoid acid standards. TPF exhibited a strong inhibitory effect on α-glucosidase with IC50 value of 5.027 ± 0.375 μg/mL, as determined via enzyme inhibition experiment and molecular docking. Additionally, the TPF significantly reduced postprandial glucose levels, as revealed via carbohydrate tolerance tests, as well as ameliorate serum lipid profiles. Therefore, pomace may be a promising resource of functional food components with therapeutic and commercial values.

Developing active and intelligent biodegradable packaging from food waste and byproducts: A review of sources, properties, film production methods, and their application in food preservation

Food waste and byproducts (FWBP) are a global issue impacting economies, resources, and health. Recycling and utilizing these wastes, due to processing and economic constraints, face various challenges. However, valuable components in food waste inspire efficient solutions like active intelligent packaging. Though research on this is booming, its material selectivity, effectiveness, and commercial viability require further analysis. This paper categorizes FWBP and explores their potential for producing packaging from both animal and plant perspectives. In addition, the preparation/fabrication methods of these films/coatings have also been summarized comprehensively, focusing on the advantages and disadvantages of these methods and their commercial adaptability. Finally, the functions of these films/coatings and their ultimate performance in protecting food (meat, dairy products, fruits, and vegetables) are also reviewed systematically. FWBP provide a variety of methods for the application of edible films, including being made into coatings, films, and fibers for food preservation, or extracting active substances directly or indirectly from them (in the form of encapsulation) and adding them to packaging to endow them with functions such as barrier, antibacterial, antioxidant, and pH response. In addition, the casting method is the most commonly used method for producing edible films, but more film production methods (extrusion, electrospinning, 3D printing) need to be tried to make up for the shortcomings of the current methods. Finally, researchers need to conduct more in-depth research on various active compounds from FWBP to achieve better application effects and commercial adaptability.

Insights into starch-based gels: Selection, fabrication, and application

Starch a natural polymer, has made significant advancements in recent decades, offering superior performance and versatility compared to synthetic materials. This review discusses up-to-date diverse applications of starch gels, their fabrication techniques, and their advantages over synthetic materials. Starch gels renewability, biocompatibility, biodegradability, scalability, and affordability make them attractive. Also, advanced theoretical foundations and emerging industrial technologies could further expand their scope and functions inspiring new applications.

Preparation of a Dual-Functional Active Film Based on Bilayer Hydrogel and Red Cabbage Anthocyanin for Maintaining and Monitoring Pork Freshness

In this study, a composite film was created with the dual goal of prolonging pork shelf life and showing freshness. Hydrogel materials as solid base films were selected from gelatin (G), sodium alginate (SA) and carboxymethyl cellulose (CMC) based on their antioxidant activity, water vapor permeability, mechanical properties, as well as their stability, antimicrobial activity, and freshness, which indicates effectiveness when combined with anthocyanins. Furthermore, the effects of several concentrations of red cabbage anthocyanin (R) (3%, 6%, 12%, and 24%) on freshness indicators and bacteriostasis were investigated. The antimicrobial activity of the composite films was evaluated against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. Likewise, the freshness indicates effectiveness was evaluated for NH3. Considering the mechanical properties, antibacterial ability, freshness indicator effect, and stability of the composite film, CS film combined with 12% R was selected to prepare a dual-functional intelligent film for pork freshness indicator and preservation. By thoroughly investigating the effect of composite film on pork conservation and combining with it KNN, the discriminative model of pork freshness grade was established and the recognition rate of the prediction set was up to 93.3%. These results indicated that CSR film can be used for the creation of active food packaging materials.

The effect of different sterilization methods on the shelf life and physicochemical indicators of fermented pork jerky

Background

To determine the effect of different sterilization methods on shelf life and physicochemical parameters of fermented pork jerky.

Methods

Various sterilization techniques, including boiling, pasteurization, medium-temperature steam sterilization, high-temperature steam sterilization, ultrasonic sterilization, and ultraviolet sterilization, were employed in this study to treat vacuum-sealed fermented pork jerky. Changes in microbial populations, physicochemical parameters, and sensory evaluations were monitored throughout the storage period.

Results

The results indicated the presence of Staphylococcus aureus on the 24th, 21st, 33rd, 24th, 18th, and 15th days in pork jerky subjected to boiling (100°C, 20 min), pasteurization (85°C, 15 min), medium-temperature steam sterilization (105°C, 0.5 Pa, 30 min), high-temperature steam sterilization (121°C, 1.0 Pa, 20 min), ultrasonic sterilization (480 W, 30 kHz, 30 min), and ultraviolet sterilization (254 nm, 100 W/m2, 60 min), respectively. Coliforms, salmonella, and Shigella were not detected in any group during storage. The medium-temperature steam sterilization method yielded the most favorable microbiological results, with an aerobic plate count of less than 1.0 lg CFU/g. However, other physicochemical parameters and sensory evaluations were moderate, with total volatile basic nitrogen (TVB-N) and thiobarbituric acid reactive substances (TBARS) measuring 14.023 mg N/100 g and 0.427 mg MDA/kg, respectively, remaining within acceptable limits.

Conclusion

Therefore, considering microbiological indicators as the primary determinant of shelf life and taking into account other physicochemical parameters, the medium-temperature steam sterilization method was identified as the most suitable approach for extending the shelf life of fermented pork jerky while preserving its flavor.

Chitosan coating with grape peel extract: A promising coating to enhance the freeze-thaw stability of beef

This study investigated the effect of chitosan coating with grape peel extracts (CH + GPE) on the physiochemical properties, protein and lipid oxidation, microstructure, and bacterial community diversity of beef during freeze-thaw (F-T) cycles. The results indicated that the CH + GPE groups had lower pH values, total aerobic count, total volatile base nitrogen, and thiobarbituric acid reactive substance values and better protection against color, water holding capacity, and sensory quality after five F-T cycles. The CH + GPE coating effectively inhibited beef microstructure destruction during the F-T cycles. High-throughput sequencing analysis revealed that the CH + GPE coating contributed to a decline in the bacterial diversity of beef and inhibited the growth of pathogenic bacteria. Interestingly, the CH + GPE coating affected the correlation between quality parameters and bacteria in beef. Consequently, the CH + GPE coating can be used as a novel packaging for preventing the loss of frozen meat quality due to temperature fluctuations.

Novel “all-in-one” multifunctional gelatin-based film for beef freshness maintaining and monitoring

In this study, a novel multifunctional food packaging was developed by incorporating alizarin (AL) and oregano essential oil Pickering emulsion (OEOP) into a gelatin film matrix. The incorporation of OEOP and alizarin improved the UV-vis resistance property of the film, blocking almost all UV-vis light (decreasing 71.80% to 0.06% at 400 nm). The elongation-at-break (EBA) was 4.02 times of that of gelatin film, indicating the improved mechanical properties of the films. This film showed a significant color change from yellow to purple in the pH range of 3-11 and a considerable sensitivity to ammonia vapor within 4 min, which was attributed to the deprotonation of the alizarin molecule. The film's antioxidant and dynamic antimicrobial capacity was significantly improved owing to the sustained release effect of OEOP. Furthermore, the multifunctional film effectively slowed down the beef spoilage rate and provided real-time visual monitoring of freshness through color changes. Additionally, the color change of the beef quality was linked to the RGB values of the film through a smartphone APP. Overall, this work broadens the possibilities of applications in the food packaging industry for multifunctional food packaging film with preservation and monitoring functions.

Improving Drying Characteristics and Physicochemical Quality of Angelica sinensis by Novel Tray Rotation Microwave Vacuum Drying

In order to improve the shortcomings of uneven heating of traditional microwave drying and to maximally maintain food quality after harvest, a rotary microwave vacuum drying equipment was fabricated and used for drying experiments on Angelica sinensis to explore the effects of drying temperature, slice thickness, and vacuum degree on drying characteristics, physicochemical quality, and microstructure of dried Angelica sinensis products. The results showed that microwave vacuum drying can significantly shorten the drying time and improved the drying efficiency. Six different mathematical models were investigated and the Midilli model was the best-fitted model for all samples (R2 = 0.99903, Pearson’s r = 0.99952), and drying methods had various effects on different indexes and were confirmed by Pearson’s correlation analysis and principal component analysis. The optimal process parameters for microwave vacuum drying of Angelica sinensis were determined by entropy weight-coefficient of variation method as 45 °C, 4 mm, −0.70 kPa. Under this condition, well preserved of ferulic acid, senkyunolide I, senkyunolide H, ligustilide, total phenols and antioxidant activity, bright color (L* = 77.97 ± 1.89, ΔE = 6.77 ± 2.01), complete internal organizational structure and more regular cell arrangement were obtained in the samples. This study will provide a theoretical reference for the excavation of the potential value and the development of industrial processing of Angelica sinensis.

Active film preparation using pectin and polyphenols of watermelon peel and its applications for super-chilled storage of chilled mutton

We investigated the effect of active packaging films prepared by pectin (WMP) and polyphenols (WME) obtained from watermelon peel on the quality of chilled mutton during super-chilled storage. The addition of WME created new chemical and hydrogen bonds in film. Furthermore, an appropriate amount of WME (≤1.5%) was evenly distributed throughout the film matrix, improving barrier properties, mechanical properties, thermal stability, and light transmittance of the film. An assessment of the meat quality showed that the pH, L*, b*, thiobarbituric acid reactive substances (TBARs), total volatile basic nitrogen (TVB-N), and total bacterial count (TCA) of super-chilled + film group were significantly lower, whereas shear force and a* value were significantly higher (P < 0.05) than other groups. The WMP/WME film has dense microstructure and excellent mechanical properties after storage. Pectin and polyphenols obtained from watermelon peel have good potential as a novel packaging material for chilled mutton during super-chilled storage.

Novel Active Food Packaging Films Based on Gelatin-Sodium Alginate Containing Beetroot Peel Extract

Currently, the exploration of natural colorants from vegetal waste has gained particular attention. Furthermore, incorporation of these natural sources into biopolymers is an encouraging environmentally friendly approach to establishing active films with biological activities for food packaging. The present study developed bioactive antioxidant films based on gelatin-sodium alginate (NaAlg) incorporated with aqueous beetroot peel extract (BPE). Firstly, the effects of combining gelatin-NaAlg and BPE at 0.25, 0.5, and 1% on the mechanical, physical, antioxidant, and antibacterial properties of the films were analyzed. With increasing BPE, mechanico-physical properties and antioxidant and anti-foodborne pathogen capacities were enhanced. Likewise, when added to gelatin-NaAlg films, BPE remarkably increased the instrumental color properties. Moreover, during 14 days of storage at 4 °C, the impact of gelatin-NaAlg coating impregnated with BPE on microbial and chemical oxidation and on the sensory characteristics of beef meat samples was periodically assessed. Interestingly, by the end of the storage, BPE at 1% limited the microbial deterioration, enhanced the instrumental color, delayed chemical oxidation, and improved sensory traits. By practicing chemometrics tools (principal component analysis and heat maps), all data provided valuable information for categorizing all samples regarding microbiological and oxidative properties, sensory features, and instrumental color. Our findings revealed the ability of gelatin-NaAlg with BPE as an antioxidant to be employed as food packaging for meat preservation.

Effects of nitrite concentrations on the quality and protein oxidation of salted meat

The objective of this study was to investigate the effects of different concentrations of sodium nitrite on the quality and protein oxidation of salted meat during 21 days of curing. The salted meat was treated with sodium nitrite at 50, 100, and 150 mg/kg for curing, and salted meat without sodium nitrite was used as a control. The results showed that in salted meat added with sodium nitrite, the carbonyl group, disulfide bond, dityrosine, surface hydrophobicity, and the transformation rate from α-helix to β-sheet were all significantly reduced, whereas the sulfhydryl group content of myofibrillar proteins was significantly increased compared to the control. Meanwhile, the total volatile basic nitrogen and aerobic plate content were significantly decreased, while both the pH and a* value were significantly increased with an increase in nitrite concentration compared to the control group. Importantly, this phenomenon was also observed in salted meat treated with low doses of sodium nitrite (50 mg/kg). In conclusion, the quality of salted beef can be improved by adding low-dose sodium nitrite to inhibit protein oxidation during the curing process. PRACTICAL APPLICATION: A low dose of sodium nitrite inhibited the rate of α-helix to β-sheet transformation of myofibrillar proteins in salted meat, reducing the exposure of hydrophobic groups and decreasing the production of protein oxidation products and TVB-N to improve the quality of salted meat. These results provided a theoretical basis and technical guidance for the application of low-dose sodium nitrite in meat processing enterprises.

Monitoring dynamic changes in chicken freshness at 4 °C and 25 °C using pH-sensitive intelligent films based on sodium alginate and purple sweet potato peel extracts

A pH-sensitive intelligent indicator film was developed and used for monitoring dynamic changes in chicken freshness at 4 °C and 25 °C by immobilizing 0.2 %-1.0 % purple sweet potato peel extracts (PPE) with sodium alginate (SA). The films presented a wide range of colors from red-pink to green-yellow at 2-13, and the films with less PPE were more sensitive to ammonia. The color of films with 0.6 % PPE changed from pink to blue when used in monitoring chicken freshness at 4 °C (5 d) and 25 °C (60 h), which corresponded to changes in total volatile base nitrogen from 5.35 (5.35) mg/100 g to 16.2 (19.9) mg/100 g. Scanning electron microscopy and X-ray diffraction revealed that PPE improved the compactness and crystallinity of SA films, while Fourier transform infrared spectroscopy revealed hydrogen bonds between SA and PPE. Compared to SA films, the water vapor and light barrier abilities of films with 0.6 % were significantly improved (P < 0.05), there was no significant effect on tensile strength (P > 0.05), and the elongation of 0.6 % PPE films (P < 0.05) was decreased. Thus, PPE can serve as an excellent indicator of intelligent films for monitoring the freshness of meat products.

Active edible films with plant extracts: a updated review of their types, preparations, reinforcing properties, and applications in muscle foods packaging and preservation

Currently, edible films have been increasingly explored to solve muscle food spoilage during storage, especially through the incorporation of plant extracts to develop edible packaging materials. Natural polymers matrices with plant extracts are befitting for fabricating edible films by casting methods. In the films system, the structure and physicochemical properties were strengthened via chemical interactions between active molecules in plant extracts and the reactive groups in the polymer chain. The antibacterial and antioxidant properties were dramatically reinforced through both physical and chemical actions of the plant extracts. Additionally, edible films imbedded with color-rich plant extracts could be considered as potential sensitive indicators to monitor the spoilage degree of muscle foods in response to change in gas or temperature. Furthermore, these films could increase sensory acceptability, improve quality and prolong the shelf life of muscle foods. In this article, the types, preparation methods and reinforcing properties of the edible films with plant extracts were discussed. Also, the applications of these films were summarized on quality maintenance and shelf-life extension and intelligent monitoring in muscle foods. Finally, a novel technology for film preparation achieving high-stability and sustained release of active compounds will become an underlying trend for application in muscle food packaging.

Antibacterial aerogels with nano‑silver reduced in situ by carboxymethyl cellulose for fresh meat preservation

Bacterial cellulose (BC) was used as a reinforcing agent, citric acid (CA) as a cross-linking agent, and CMC@AgNPs as antibacterial nanomaterials, in which CMC@AgNPs were reduced from AgNO₃ in situ by carboxymethyl cellulose (CMC) as a reducing agent and stabilizer to fight microbial corruption. Its potential application in packaging fresh meat has been investigated. Results showed that the antibacterial CMC@AgNPs/BC/CA aerogels with excellent structural integrity and outstanding water absorption were developed by adding 0.3% BC and 0.25% CA. The CMC@AgNPs/BC/CA aerogel significantly reduced the color change and the total viable bacterial counts (TVC) in fresh meat after 7 days of refrigerated storage. The results indicated that CMC@AgNPs/BC/CA aerogels can effectively extend the shelf life of fresh meat, and can be used for meat packaging as a biologically active absorption pad.

Effects of ultrasound pretreatment on the quality, nutrients and volatile compounds of dry-cured yak meat

The objective of the present study was to assess the effects of ultrasound pretreatment on the quality of dry-cured yak meat. The ultrasonic power with 0, 200, 300 and 400 W (ultrasonic frequency of 20 kHz) were used to assist processing of dry-cured yak meat. The meat quality, nutrient substances, sensory quality, electronic nose, electronic tongue and volatile compounds of dry-cured yak meat were determined. The results indicated that the moisture content and hardness value of ultrasonic treatment group was significantly lower compared to the control group (P < 0.05). Ultrasonic treatment increased the value of b*, and decreased the value of L*, a*, pH, chewiness, melting temperature and enthalpy. Springiness value significantly increased from control group to 300 W of ultrasonic power group. Shear force significantly decreased with the increase of ultrasonic power (P < 0.05). Ultrasonic treatment had no effect on the TVB-N content, but it could increase the TBARS content. Ultrasonic treatment could significantly increase the essential FAA (EFAA) and total FAA (P < 0.05). In addition, the saturated fatty acid (SFA) content significantly increased with the increase of ultrasonic power (P < 0.05). Ultrasound treatment negatively affected the meat's color, smell, and taste but increased its tenderness and the overall acceptability. It also significantly increased alcohols and aldehydes contents (P < 0.05), which were consistent with the measurement of electronic nose and electronic tongue. The results demonstrated that the the appropriate ultrasonic power assisted in the processing improves quality of dry-cured yak meat, particularly for the power of 300 W.

Impacts of chitosan nanoemulsions with thymol or thyme essential oil on volatile compounds and microbial diversity of refrigerated pork meat

This study aimed to investigate the effects of antibacterial substances embedded in nanoemulsions on the volatile compounds and the bacterial community composition of refrigerated pork stored at 4 °C for 12 days, and to evaluate the relationship between volatile components and bacterial diversity of refrigerated pork. As compared to the control (CK) group, the treatment groups (thyme essential oil chitosan nanoemulsions (TEO-CS), thymol chitosan nanoemulsions (T-CS) and chitosan nanoemulsions (CS)) showed lower TVB-N values, pH values, TBARs values and better protective against color degradation. The E-nose and GC-MS evaluation indicated that compounds causing unpleasant odors could be inhibited in the T-CS and TEO-CS groups. In addition, high-throughput sequencing showed that Pseudomonas (18.3%), Lactococcus (27.0%) and Acinetobacter (38.8%) were predominant genera of refrigerated pork in the early storage period. At day 12, Pseudomonas (84.3%) increased rapidly in the CK group and became the main microbiota. By contrast, both coatings changed the microbial composition, reduced the proportion of spoilage organisms and retained bacterial diversity. Therefore, chitosan nanoemulsions with antibacterial substance could be considered as an effective supplementary and method to improve the preservation effect of fresh pork, which provides a solution to against conventional packaging and extend the shelf-life of meat.

Dynamics of heat transfer and moisture in beef jerky during hot air drying

The aim of this study was to investigate the surface temperature, moisture migration, muscle shrinkage and microstructure of beef jerky during hot air multi-stage drying. Temperatures were sequentially increased from 40 to 50 to 60 °C, and corresponding times were 0.5 h - 1 h - 2.5 h, 0.5 h - 2 h - 1.5 h, 1 h - 1 h - 2 h and 1 h - 2 h - 1 h in 4 groups. With increasing temperature, moisture content and diffusivity of the sample decreased, the surface temperature, moisture migration, muscle shrinkage and the gaps (spacing) between muscle fibres increased. The jerky in groups 3 and 4 attained high overall acceptability. The jerky dried at 40 °C for 1 h, 50 °C for 1 h and 60 °C for 2 h had highest quality. The results cover the range of temperature and time used in beef drying and can be used to optimize the drying process of beef.

Changes in chilled beef packaged in starch film containing sea buckthorn pomace extract and quality changes in the film during super-chilled storage

This study aimed to evaluate the effects of super-chilled storage (-1.3 °C) combined with starch film packaging containing different contents of sea buckthorn pomace extract (SSF, 0, 1, 2, and 3%, w/w) on the quality of chilled beef. The release kinetics, microstructure, and mechanical properties of the film were also measured to investigate its suitability for super-chilled storage. The results of the meat quality assessment showed that the L*, a*, and sensory evaluation values of the SSF-3% samples were significantly higher (P < 0.05), and the pH, b*, thiobarbituric acid reactive substance (TBARS), total volatile basic nitrogen (TVB-N), and total viable count (TCA) were significantly lower (P < 0.05) than the SSF-0%. The release of SBP from the SSF film was controlled by diffusion. Furthermore, SSF-3% was found to have a compact microstructure and good mechanical properties at the end of the super-chilled storage. The results demonstrated that SSF is an effective packaging material for beef at super-chilling temperatures.

Application of ε-polylysine in extending the storage period of pork jerky

In this experiment, natural nontoxic preservative ε-polylysine (ε-PL) was used as a natural preservative in pork jerky. The pork jerky samples with ε-PL (experimental group) and without ε-PL (blank group) were stored at the 27 and 37℃. Then, the number of microorganisms, total volatile basic nitrogen (TVB-N), pH, and water activity (Aw) of each group were tested to test the antiseptic effect of ε-PL. The results showed that due to the Staphylococcus aureus was detected, the storage period of the blank group at 27 and 37°C was 15 and 9 days, respectively. However, Coliforms, Staphylococcus aureus, Salmonella, and Shigella were not detected in the experimental group on the 60th day. The experimental group all accord with the national standard for the quantity of microorganisms in meat jerky. The TVB-N content of the blank group reached 14.00 mg/100 g (15th day, 27°C) and 14.93 mg/100 g (9th day, 37°C) at the end of the storage period, while the TVB-N content of the experimental group was 11.20 mg/100 g (60th day, 27℃) and 15.86 mg/100 g (60th day, 37℃), and the increase rate of TVB-N in the blank group was greater than the experimental group, indicating that ε-PL can play a better microbial stabilization effect in pork jerky. The test of pH and Aw showed that ε-PL can stabilize the quality of pork jerky. Finally, the antiseptic effect of ε-PL was comparable to many chemical preservatives. This experiment confirms that ε-PL played an important role in extending the storage period of pork jerky.

Polysaccharide based films and coatings for food packaging: Effect of added polyphenols

There has been keen interest in developing biodegradable food packaging materials using polysaccharides. Plant polyphenols are natural antioxidants with many health effects. Different types of plant extracts rich in polyphenols have been formulated into polysaccharide based films and coatings for food packaging. The packaging increases the shelf life of food products by decreasing the quality loss due to oxidation and microbiological growth. The release of polyphenols from the films is modulated. Polysaccharide films incorporated with certain types of polyphenols can be used to indicate the freshness of animal based products. To formulate films with desirable mechanical and barrier properties, addition levels and types of plant extracts, plasticisers and composite polysaccharide materials used should be optimized. The potential of polysaccharide based films with added polyphenols to stop the SARS-CoV-2 transmission through food supply chain is discussed. Polysaccharide based films fortified with polyphenol extracts are multifunctional with potential for active and intelligent packaging.

Effect of wet sea buckthorn pomace utilized as an additive on silage fermentation profile and bacterial community composition of alfalfa

To effectively preserve nutrients, alfalfa silage was treated without (control) or with Lactobacillus plantarum (LP) and their mixture (LP + SBP). Results showed that SBP decreased (P < 0.05) final pH value and ammonia-N of total N, increased (P < 0.05) lactic, acetic and propionic acid contents, resulting in more residual water soluble carbohydrate and crude protein contents and less fiber content in relative to control. Moreover, SBP decreased (P < 0.05) the number of observed species, richness index of ACE and diversity index of Shannon at early stage of ensiling, while Lactobacillus plantarum, Lactococcus lactis, and/or Lactobacillus brevis dominated in silages. In particular, LP + SBP enhanced the growth of Lactococcus lactic at early stage and Lactobacillus plantarum at late stage of ensiling, resulting in higher lactic and acetic acid contents and lower propionic acid content as compared with LP. These confirmed that SBP could be used as an additive for improving silage quality of alfalfa.