NFS Journal最新文献

The inhibition exerted by ethanolic extracts of coffee mucilage on the growth of bacteria was studied by microdilution in agar. The growth inhibition effect was evaluated for pathogenic or food spoilage related bacteria (Pseudomonas aeruginosa (ATCC 27853), Alcaligenes sp. (UCR277), Serratia sp. (UCR299), Micrococcus luteus (ATCC4698), Escherichia coli (ATCC35150), Staphylococcus aureus (ATCC25923), Bacillus cereus (ATCC14579), Salmonella enterica subsp. enterica (ATCC 13311) and Listeria monocytogenes (SLCC4013)) and for bacteria associated with human intestinal biota (Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus rhamnosus, Lactiplantibacillus plantarum subsp. plantarum). The most effective growth inhibition was observed for B. cereus (ATCC14579). The content of chlorogenic acid and caffeine in the ethanolic extracts was quantified by HPLC/DAD. The chlorogenic acid content in the extracts ranged from 2.67 to 4.76 mg/ml, while the caffeine content ranged from 1.24 to 6.48 mg/ml. Although ethanolic extracts of coffee berry mucilage inhibited the growth of B. cereus, this inhibition does not seem to be related to the caffeine or chlorogenic acid contents.

Opuntia ficus-indica fruits are outstanding for their sensory attributes and multiple health benefits. However, this fruit is highly perishable, and substantial efforts have been carried out to extend its shelf-life. Lactic fermentation of fruits by-products using autochthonous bacteria arises as relevant technology for preserving vegetables and their by-products. In this study, autochthonous Lactiplantibacillus plantarum and Fructobacillus fructosus strains previously selected from Opuntia ficus-indica fruits of Northwestern Argentina were characterized according to their technological and functional properties to select the most suitable for the production of fermented cactus pear products. L. plantarum strains showed better acidifying activity, decreasing the pH of the juice by about 2.9 units in 24 h. All the strains studied produced lactic and propionic acids, and L. plantarum S-811 and S-TF2 strains and F. fructosus S-TF7 strain were the better lactic acid producers, with values around 9.5 g/l. These strains also displayed antimicrobial activities against undesirable pathogen bacteria, showed a safety profile typical of lactic acid bacteria, and the juice fermented with these strains preserves the phenolic compounds content and antioxidant activity of unfermented juice. The obtained results showed the potential of L. plantarum S-811 and S-TF2, and F. fructosus S-22 for their use as starters for the fermentation of cactus pear by-products, standing out L. plantarum S-811 for its potentiality to elaborate a fermented cactus pear beverage. The cactus pear juice fermented by L. plantarum S-811 showed physicochemical and microbiological stability that favors juice shelf-life. Besides, fermentation conferred distinctive sensory features to the cactus pear juice without influencing consumers' overall acceptability.

The aim of this study was to assess the effects of ultrafiltration (UF) combined with high-pressure processing (HPP) or heat treatment on the quality of soft cheese produced from camel milk (CM) or bovine milk (BM). Milk was concentrated by UF (0, 1, and 2-fold) before treatment with HPP at 350 MPa or 550 MPa for 5 min at 4 °C or by pasteurization at 65 °C for 30 min or at 75 °C for 30 s. Cheeses were produced using starter cultures and camel chymosin and pH, yield, proximate composition, texture profile, rheological properties, and protein profiles were determined. The highest yield of BM cheese (26%) was observed under the treatment with 2-fold UF combined with HPP at 550 MPa. CM cheese had the highest storage and loss moduli as well as the total solid and protein content under this treatment. According to SDS-PAGE electrophoresis, CM cheeses were more susceptible to proteolysis and had a higher number of low-molecular-weight bands, indicating the involvement of some active enzymes compared with BM cheeses. In conclusion, UF combined with HPP can enhance the cheese total solid content and gel structure in CM cheese products compared with heat treatment.

Histamine producing foodborne pathogens pose a major microbiological risk in the overall seafood products. Specifically, negative health effects of histamine poisoning from seafood products after processing is a food safety and human health concern globally. Therefore, it is essential to advance sustainable and inexpensive post-harvest processing strategies to counter this serious food safety and health challenge and to improve overall food quality of common seafood product like tuna fish. Based on these food safety and health quality needs, the aim of this study was to investigate the effectiveness of the combination of Lactiplantibacillus plantarum BY-45 and salt concentration to control histamine formation in vitro and in vivo on sample filet of tuna fish during processing to reduce this microbiological associated health risk. Isolation and identification of histamine forming bacteria in tuna loin and optimal storage temperature for inhibiting histamine formation was determined with L. plantarum BY-45 treatment. In this study, Escherichia coli belonging to Enterobacteriaceae family was found to be the predominant histamine forming bacteria contaminating our tuna samples. This contamination was suspected to happen during handling after catch and prior to landing at Benoa harbor, Bali for further processing. However, the rate of histamine formation was significantly suppressed (<1 ppm) at temperature of ≤2°C, which was significantly lower than 79.73–88.33 ppm that was produced at 4°C. Additionally, in response to LAB and salt combination, histamine formation by E. coli was totally suppressed. The results of this study were consistent in the in vivo assay on loins of tuna samples. Overall, this study provides the foundation to reduce microbiological food safety risk from histamine poisoning by foodborne pathogens in tuna, and beneficial LAB based strategy can be targeted to achieve wider food safety and health quality benefits in processed seafood.

Background

Complementary foods are provided to newborns and early children to replace breast milk, which, after six months of exclusive breastfeeding, is no longer adequate to meet the child's nutritional needs. However, foods like dairy, grains like maize, sorghum, and millet, as well as nuts like groundnuts, which are frequently suggested as supplemental foods have all been linked to aflatoxin contamination. Understanding how caregiver preparation and storage practices of complementary flour affect children's aflatoxin exposure is crucial.

Objective

To determine the prevalence of dietary exposure to aflatoxin and its associated factors in children aged 6–23 months complemented with cereal-based foods in the Bukombe District of Geita Region in Tanzania.

Methodology

An analytical cross-sectional study was used to survey 342 households of children aged 6–23 months. Fifty complementary flour samples from 50 of the total households were chosen at random and tested for aflatoxin using the HPLC technique and standard methods. A semi-structured questionnaire was used to assess parents'/caregivers' food handling and preparation practices and the amount of food consumed. The obtained results were used to estimate aflatoxin dietary exposure of children in the study.

Results

Most of the children (86%) were exposed to aflatoxin through diet with a median value of 0.3 μg/kg-bw/day mainly linked to age and breastfeeding status. The majority of the exposed (86%) were above the reference limit of 0.04 μg/kg-bw/day. Most parents (98.5%) chose maize as the main component of complementary flour, either on its own or mixed with other cereals and winnowing and dehulling as the most and least common practices with the proportion of 78.9% and 9.4% respectively. Furthermore, a majority (88%) of flour samples were contaminated with aflatoxin B1 and total aflatoxin with log mean values of 1.2 ± 0.81 and 1.5 ± 0.68 μg/kg respectively which were above the Tanzania reference limit of 5 μg/kg and 10 μg/kg respectively. Contamination was significantly (p < 0.05) associated with location (Fisher's exact value = 6.68, p = 0.036), source of cereals (Fisher's exact value = 56.4 p = 0.025), and storage time (Fisher exact value = 23.8, p < 0.001).

Conclusion

In view of the findings, aflatoxin contamination in flours used for complementary feeding was beyond tolerable limits, hence increasing the risk of children's dietary exposure. This suggests that strengthening strategies to control aflatoxin contamination of maize throughout the food chain and teaching parents about preparation and storage methods that reduce aflatoxin in cereals/flour are important.

Sous-vide is a cooking technique which is considered safe for food preparation, however, the recommended temperatures and times for preparing seafood and fish may not be sufficient to ensure safety, and additionally, thermal stress may cause changes in virulence and resistance. The objective of the present investigation was to determine the reduction of Listeria monocytogenes isolated from fish after sous-vide preparation. For this purpose flow cytometry was used. The impact of stress during the preparation of the fish-based dish using the sous-vide technique on the virulence potential and resistance profile was determined geno- and phenotypically. The study was conducted at four different temperatures, that are typical for fish preparation (42, 52, 57 and 60 °C) showing that none of them could be effective against L. monocytogenes. In addition, the investigation of changes in the virulence, phenotypic antibiotic resistance and gene expression showed that the stress during the preparation of sous-vide decrease virulence potential of the L. monocytogenes strains. It was observed that the greatest changes in antibiotic resistance profile were noted for tetracycline and notable changes were also observed for some strains in the case of fosfomycin and ciprofloxacin. Therefore it is important not to consider the sous-vide method as ensuring the microbiological quality of products, especially those with high contamination levels, and choose products of the best quality for processing.

This study intends to explore the antihyperglycemic effect and the possible hypoglycemic mechanism of garlic (Allium sativum L.) polysaccharide (GP) using an animal model. Kunming mice were fed with GP (1.25, 2.5, 5.0 g/kg‧bw) for five weeks after insulin resistance (IR) engendering by a high-oil-high-sugar diet and streptozotocin (STZ). Intragastric administration of GP effectively improved the disease of polyphagia and polydipsia in diabetic mice. The fasting blood glucose (FBG) in the high-dose GP (DGH) group was meaningfully 42% lower than that in the diabetic model (DC) group showing its hypoglycemic effect. GP might manipulate hepatic glycogen metabolism by regulating the content of glucokinase (GK), glycogen synthase (GS), and phosphoenolpyruvate carboxykinase (PEPCK). Results showed that GP with a low relative molecular weight (MW) of 2.0 kDa consisted predominately of a 2,1-β-D-Fruf backbone with 20.7% side chains owning the structure-effect on hypoglycemia indicating it could be a potential supplement for the intervention and management of hyperglycemia.

Sea buckthorn berries contain numerous bioactive lipids such as fatty acids, carotenoids, tocols, and sterols. Among fatty acids, a high concentration of rare in nature palmitoleic acid is characteristic of sea buckthorn pulp oil. We previously showed the potency of pulp oil from the Luczystaja cultivar to augment glucose-induced insulin secretion in pancreatic β cells. Since the composition of sea buckthorn berries varies depending on the cultivar, here we compared the activity of oleosomes from Botaniczeskaja Ljubitelskaja, Golden Rain, Prozracznaja, Maryna and Luczystaja cultivars in two different pancreatic cell lines, a mouse MIN6 and human EndoC-betaH1. Besides the characterization of particle size and ζ-potential, we evaluated the influence of crude and digested oleosomes on cell viability, insulin secretion, and intracellular calcium mobilization. Additionally, the antioxidant activity measured with the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) radical cation-based assay was determined and compared.

Vitexin is a C-glycosylated flavonoid which has many biological activities. However, extremely low aqueous solubility and poor bioaccessibility of vitexin greatly limits its application. In this study, phytosome technology was applied to improve these limitations using soybean phosphatidylcholine (SPC) and egg yolk phosphatidylcholine (EPC) as carrier agents. The effect of types of carrier agents and ratios of vitexin to carrier agent on the physicochemical properties, solubility, and thermal stability of vitexin-loaded phytosomes was investigated. The phytosome produced using EPC showed high encapsulation yield of 97.60%, encapsulation efficiency of 98.27%, solubility of 89.15%, total phenolic content (TPC) of 114.44 mg GAE/g phytosome, ferric reducing antioxidant power (FRAP) of 15.77 mmol Trolox/g phytosome and DPPH radical scavenging activity of 9.49 mmol Trolox/g phytosome. The phytosomal preparations using the ratio of vitexin to EPC of 1:3 could improve physical and chemical properties of vitexin-loaded phytosomes. Furthermore, phytosome technology could promote greater bioaccessibility and antioxidant activity of vitexin under thermal and simulated gastrointestinal digestion conditions compared to unprocessed vitexin. The results suggest that phytosome technology has ability to overcome the limitation and enable the application of vitexin.