Food and Bioproducts Processing最新文献

In this study, antimicrobial nanocomposites based on low-density polyethylene (LDPE) and calcium oxide nanoparticles (CaO) were developed for potential use in food packaging. CaO nanoparticles, averaging 5.6 ± 1.8 nm in diameter, were synthesized from eggshells and surface-modified with oleic acid (O-CaO). Nanocomposites were prepared via melt-blending, incorporating nanoparticles into neat LDPE at 5 and 10 wt% concentrations. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses revealed improved distribution and dispersion of O-CaO nanoparticles within the polymer matrix compared to unmodified CaO. This enhanced dispersion increased the crystallinity percentage (%X_c) of LDPE/O-CaO from 14 % to 18 %. Mechanical testing showed a 22 % increase in Young’s modulus for nanocomposites with 5 wt% O-CaO, with dynamic mechanical thermal analysis (DMTA) confirming increased stiffness at low temperatures. The nanocomposite films exhibited high antimicrobial efficacy, reducing Escherichia coli populations by over 74 %, dependent on nanoparticle surface modification. These findings suggest that LDPE/O-CaO films are a promising alternative for antimicrobial food packaging applications.

This review explores the potential of agri-food waste materials, with a particular focus on macadamia nut by-products. Industrial processing of macadamia nuts yields a significant volume of by-products, including green husk and woody shell. Recent research has highlighted these by-products as readily available, cost-effective rich sources of phenolic compounds, renowned for their potent antioxidant and antibacterial properties. This paper emphasizes the importance of selecting an optimal extraction method to fully harness the bioactive potential of these phenolic compounds. In this work, we provide a comprehensive overview of conventional and advanced extraction techniques that are used to extract phenolic compounds from macadamia by-products, with a particular focus on the methods applied to macadamia green husk. Among the various techniques, it appears that ultrasound-assisted extraction, especially when combined with aqueous organic solvents, is more efficient than other methods for this purpose. This review also addresses the challenges in phenolic compound recovery, primarily due to the lack of a standardized extraction process. This often results in the extensive use of extraction solvents to achieve an extract that is rich in phenolic compounds. Overall, this research offers a valuable understanding of the most effective methods for the extraction and recovery of phenolic compounds from macadamia by-products and discusses the potential for scaling up these extraction processes. Hence, it can serve as a useful resource for researchers and industry professionals interested in sustainable and efficient utilization of by-products of the nut industry.

Pectinases are a diverse group of enzymes that play a crucial role in modifying or breaking down complex pectic substances. Pectinases are widely distributed among bacteria, fungi, and plants. The global demand for microbial pectinase has significantly increased due to its broad applicability and efficient catalytic capabilities across multiple industries including food processing, textiles, and biofuel production. Their commercial production often relies on expensive substrates, contributing to economic inefficiency and environmental burdens. Utilizing agro-industrial waste and microorganisms for pectinase production offers a rational solution to two interconnected challenges: the cost-effectiveness of enzyme production and the environmental impact of waste generation. Moreover, the valorization of waste materials not only contributes to efficient enzyme production but also exemplifies a circular approach by minimizing environmental impact and promoting sustainable resource efficiency to bioprocessing. This review offers a thorough examination of microbial pectinases, including their production from agro-industrial waste, their various industrial applications, and the current market landscape. It also delves into recent advancements in enzyme development and optimization techniques that have significantly boosted the efficiency and cost-effectiveness of pectinase production. By highlighting these developments, the review emphasizes the potential for this approach to enhance industrial practices and contribute to environmental sustainability.

Microbial polysaccharides have been gaining growing interest often as alternative to animal derived products or as sources of novel features for biotechnological applications. Process production costs, however, are still high. A possible solution to that exploits agri-food and dairy industrial byproducts as fermentation substrates. This approach also reduces the need for cost-intensive disposal treatments for these waste sources and supports green and circular economy policies. Therefore, as for other microbial glucuronic acid-based biopolymers (e.g. hyaluronic acid, alginate), in this perspective, wild type and engineered E. coli K4 were used in this work as cell factories to produce K4 capsular polysaccharide (CPS) from renewable sources. The backbone of the K4 CPS, chondroitin, is the precursor of chondroitin sulfate (CS), a glycosaminoglycan found in animal tissues that is extensively used for curing osteoarthritis and studied for several other emerging biomedical applications. Interestingly, also chondroitin showed promising bioactivity in vitro and in vivo. Due to its high availability from local companies, second cheese whey (SCW), a worldwide copious and polluting liquid waste, was used as fermentation substrate in this work. Results showed that SCW fully supports growth of wild type and recombinant E. coli K4 strains, and demonstrate, for the first time up to date, the production of K4 CPS from liquid waste as proof of principle. Batch processes in 3 L fermenters indicated a 100 % improvement of the polysaccharide yield and allowed the production of 1.1±0.1 g/L of product from the recombinant strain with very low accumulation of acetic acid, demonstrating that SCW by itself fully supports polysaccharide production.

Casein is the most abundant protein in milk with good emulsifying properties and bioavailability. However, the tight micellar structure of casein results in poor solubility. In the case of soft solid materials such as processed cheese, imitation cheese, yoghurt and protein-based oil-in-water emulsions, poor solubility directly affects the homogeneity and stability of the texture structure of such products, leading to a poor user experience. In this study, two protein modification techniques, hydrolysis and succinylation, were combined to improve the solubility of casein and the stability of its emulsions. The individual and combined effects of enzymatic hydrolysis and succinylation modification approaches on the stability of rennet casein (RC) and micellar casein (MC) emulsions were further explored. After double-treatment of casein with enzymatic hydrolysis and succinylation, the solubility of RC and MC was up to about 95 %, which was superior to that of single-treatment. Fourier transform infrared spectroscopy showed that the characteristic wave signals of the double-treated samples were located between the two single-treated samples, and that there may be an opposite effect between the two modifications. After 21 days of storage, the emulsions prepared from double-treated caseins still remained stable. The salt ionic stability and freeze-thaw stability were significantly improved, and the physical stability of MC was increased by nearly three times. The results explained the effects of enzymatic hydrolysis and succinylation on the functional properties of casein, provided a reference for the development of food systems based on oil-in-water emulsions, and offered a new idea for the wide application of succinylated casein.

Tenderness is one of the most important criteria in bovine meat, as it determines whether the meat is used for grilling, long-time cooking or post-processing. It is therefore of great interest for the industry to measure it. Common systems require the extraction and destruction of samples, inducing time and material expenses. In this article, a new nondestructive characterization apparatus, based on monitored indentation, relaxation, and recovery, is proposed. Samples from two cuts known for their difference in tenderness were used from the same carcass. Their tenderness were assessed via compression tests and then compared to indicators from the force–displacement measurements. Results showed that the indentation and recovery speed, and the force relaxation enable the differentiation of the two cuts ($p<0.05$). These results were obtained on samples from a single carcass. Measurements on other carcasses should be performed to ensure that the results presented in this article can be generalized to bovine meat.