Anti‐obesity effect of feeding probiotic dahi containing Lactobacillus casei NCDC 19 in high fat diet‐induced obese mice

Nowadays, studies about the anti‐obesity potential of probiotics are of growing interest. Lactobacilli are one of the well‐studied probiotics owing to their preventing effect on metabolic disorders. This study was undertaken to access the anti‐obesity effect of probiotic dahi containing Lactobacillus casei NCDC 19 on C57BL/6 mice. Feeding of probiotic dahi showed reduce body weight gain and epididymal fat weights. Moreover, blood glucose, plasma lipids and expression level of leptin were reduced and caecal bifidobacteria counts and adiponectin expression levels were significantly increased. It can be concluded that feeding of probiotic dahi containing L. casei NCDC 19 showed potential anti‐obesity effects.     

Evaluation of physico‐chemical properties,trace metal content and antioxidant activity of Indian honeys

In this study, effect of plant sources viz. Gossypium hirsutum, Coriander sativum, Murraya koenigii and Dalbergia sisso on twelve physico‐chemical properties, phenolic content, flavonoids content as well as on trace mineral (Fe, Cu, Ni, Mn, Cd and Pb) contents of honey were investigated and compared. All the physico‐chemical values were in the range of approved limits of European Commission Regulation and the source of honey had a significant (P < 0.05) effect on physico‐chemical properties, phenol content, flavonoid content and trace mineral content. The results of positive correlations between physico‐chemical properties (colour and antioxidant properties) and compositional components (phenols and flavonoids content) established that antioxidant properties were dependent on source of honey rather than on colour of honey. Pattern recognition methods such as principal component analysis and linear discriminate analysis were performed to classify honey on the basis of physico‐chemical properties, phenolic content, flavonoids content and trace metal content. The variables proline and lead exhibited higher discrimination power.     

In vitro antioxidant and in vivo xanthine oxidase inhibitory activities of Pandanus amaryllifolius in potassium oxonate‐induced hyperuricemic rats

Xanthine oxidase (XO) plays an important role in the regulation of uric acid and prevents it from being overproduced as in hyperuricemia disease. The combined effects of antioxidant and xanthine oxidase inhibitor would become a promising approach for hyperuricemia treatment. In this research, the antioxidant and xanthine oxidase inhibitory activities of Pandanus amaryllifolius leaf were evaluated. The leaf water extract (PA‐W) showed highest total phenols, and petroleum ether extract (PA‐PE) showed highest total flavonoids contents. The antioxidant activity of DPPH, metal chelating and hydrogen peroxide was highest in PA‐W extract. The treatment of PA‐W extract at 1000 mg kg^?1 body weight in potassium oxonate‐induced hyperuricemic rats showed significant (P < 0.001) decrease in serum uric acid level by 85% and XO activity by 64%, respectively, as compared to the hyperuricemic rats. In conclusion, the P. amaryllifolius possess the dual effect of antioxidant and XO inhibition as potential therapeutic agents in the hyperuricemia treatment.     

‘Lipase and protease production of dairy Penicillium sp. on milk‐protein‐based solid substrates’

The lipolytic and proteolytic activity of Penicillium camemberti PC TT033 and Penicillium roqueforti PR G3, cultured on the whey solids or simulated cheese media, were compared under several pH reaction conditions. Lipolytic activity was higher when both strains had been cultured on the whey medium than on the simulated cheese medium, whereas proteolytic activity was less influenced by the culture medium. The relationship between the reaction pH and these enzyme activities was dependent on the culture medium, which suggested that the expression level and balance of isozyme rely on the culture substrate.     

The effect of enzymatic hydrolysis on the biological properties of Oenothera biennis,Borago officinalis and Nigella sativa seedcake by‐products from oil pressing

The biological properties of ethanolic (50%, v/v) extracts from Oenothera biennis, Borago officinalis, Nigella sativa seedcake before and after enzymatic hydrolysis by alpha‐amylase (EC 3.2.1.1) from Aspergillus oryzae, beta‐glucosidase (EC 3.2.1.21) and beta‐glucanase (EC 3.2.1.6) from Aspergillus niger combinations in a ratio of 1:1:1 were investigated. Total phenolic, flavonoid and reducing sugar content for O. biennis extract after enzymatic hydrolysis was, respectively, 0.5, 1.5 and 2 times higher in comparison with nonhydrolysed extract. Iron‐chelating and radical‐scavenging activity of O. biennis seedcake extract after hydrolysis (IC₅₀ = 0.076 mg mL^?1 and IC₅₀ = 0.050 mg mL^?1) was at a similar level as that nonhydrolyeed (IC₅₀ = 0.070 mg mL^?1 and IC₅₀ = 0.065 mg mL^?1). The antioxidant activity was two times higher after hydrolysis than before enzymatic hydrolysis of O. biennis seedcake extract. Also strong elastase inhibition activity has been shown to O. biennis seedcake extract before (IC₅₀ = 0.095 mg mL^?1) and after enzymatic hydrolysis (IC₅₀ = 0.07 mg mL^?1), respectively. Oenothera biennis and B. officinalis seedcake extracts before and after hydrolysis have stronger antibacterial activity against Pseudomonas aeruginosa strain in comparison with N. sativa seedcake.     

Thermo‐rheological and functional properties of gamma‐irradiated wholewheat flour

The effects of different doses (0, 0.5, 1, 2.5, 5 and 10 kGy) of gamma irradiation on the thermal, rheological and functional properties of the wholewheat flour were evaluated. Water and oil absorption capacity of the flour increased from 85.92% to 91.44% and 1.10 to 1.91 g g^?1 of flour, respectively, with increase in irradiation dose. The dough development time decreased with dose from 4.0 to 3.0 min. The transition temperatures (T_o, T_p and T_c) decreased as the dose increased; enthalpy of gelatinisation (?H) decreased from 5.18 to 4.27 J g^?1 with dose. The flow behaviour showed a shear‐thinning behaviour, and the hysteresis area decreased with dose. The structural recovery decreased with dose. FTIR did not show formation of any new chemical groups.     

Limited hydrolysis of β‐casein by cell wall proteinase and its effect on hydrolysates's conformational and structural properties

Optimisation of enzymatic hydrolysis of β‐casein with cell envelope proteinase (CEP) from Lactobacillus acidophilus JQ‐1 to produce the angiotensin‐I‐converting enzyme (ACE) inhibitory peptides using response surface methodology (RSM). Under optimal conditions (enzyme‐to‐substrate ([E]/[S]) ratio (w/w) of 0.132 and pH of 8.00 at 38.8 °C), the ACE inhibitory activity of hydrolysates was 72.06% and the total peptides was 11.75 mg mL^?1. Scanning electron microscopy (SEM) micrographs indicated that the tightness of the β‐casein surface structure was gradually weakened and small holes appeared after enzymatic treatment, while Fourier transform infrared spectroscopy (FTIR) spectra indicated remarkable changes in the chemical composition and macromolecular conformation of β‐casein after enzymatic hydrolysis. Differential scanning calorimetry (DSC) analysis indicated that the corresponding hydrolysates had higher thermal stability. The enzymatic hydrolysis also led to an increase in the free sulfhydryl content of β‐casein hydrolysates compared with raw β‐casein, which led to the increase in the antioxidant activity of β‐casein hydrolysates.     

Development and validation of a SYBR‐Green I Real‐Time PCR test to detect bivalves including Mytilus species in foods

The incidence of allergy to seafood, and in particular to molluscs is second only to that of nuts. To protect consumers, the regulators of food products insisted on identifying molluscs as allergens. The aim was to develop quantitative assay for the presence Mytilus species in processed food products. The chosen platform was real‐time PCR (qPCR) targeting either the gene encoding mitochondrial cytochrome C oxidase I or the nuclear gene encoding β‐actin. Recombinant plasmids containing each of target regions were used as a reference for quantification purposes. Limit of detection (LOD) and of quantification (LOQ) were determined. Spiked food samples containing 50–500 μg g^?1 of Mytilus chilensis were analysed both by qPCR and by ELISA. The former assay gave a positive outcome over this range, whereas the latter was sensitive down to a concentration of 125 μg g^?1.     

Effect of nisin‐producing Lactococcus lactis starter cultures on the inhibition of two pathogens in ripened cheeses

The effect of Lactococcus lactis nisin‐producing strains, isolated from Italian fermented foods, on the survival of two foodborne pathogens namely Listeria monocytogenes and Staphylococcus aureus was investigated in experimental cheese production. One of the three Lactobacillus lactis nisin innoculated as starters, Lactobacillus lactis 41FL1 lowered S. aureus count by 1.73 log colony‐forming units (cfu)/g within the first 3 days, reaching the highest reduction, 3.54 log cfu/g, by the end of ripening period of 60 days. There was no effect on L. monocytogenes. The application of L. lactis 41FL1 as bioprotective culture in controlling S. aureus shows considerable promise.     

Effect of thermosonication in a batch system on the survival of spore‐forming bacteria

Thermosonication may help reduce bacteria counts responsible for spoilage in dairy products. Vegetative cells and spores of Geobacillus stearothermophilus, Anoxybacillus flavithermus and Bacillus subtilis (spores only) were treated with either heat alone or thermosonication in a batch system from 0 to 120 s in tryptic soy broth and 2% fat milk at 72 and 73 °C. D‐values for vegetative cells were calculated and were reduced after thermosonication. Maximum reduction in vegetative cells after thermosonication was 1 log after 30–45 s and for spores was ≤0.2 log after 120 s, which may not influence dairy product quality in scale‐up systems.     

Detection and quantification of Escherichia coli and Pseudomonas aeruginosa in cow milk by near‐infrared spectroscopy

This work investigated the potential of NIR technology to be applied in the dairy industry for the detection of micro‐organisms. To this end, two types of cow milk samples were studied, one in which only bacterial biomass was considered and the other in which bacteria were cultured and grown in milk for 24 h. The study was carried out using two micro‐organisms Escherichia coli and Pseudomonas aeruginosa. Both types of samples with different counts of both micro‐organisms were analysed by a NIR analyser in the range 10 000–4000 cm^?1 based on transmittance measurements. Multivariate models indicated that a better discrimination between micro‐organisms was attained in those milk samples in which micro‐organisms have been grown.     

Synergistic effect between Helichrysum italicum essential oil and cold nitrogen plasma against Staphylococcus aureus biofilms on different food‐contact surfaces

Staphylococcus aureus is the most common pathogen in human, and the most diseases produced by S. aureus are associated with biofilms. Helichrysum italicum essential oil (EO), as a natural and safe spice, was employed to disperse S. aureus biofilm by cold nitrogen plasma (CNP) assist. After S. aureus biofilm formation on food container surfaces, they were exposed to CNP and then treated with Helichrysum italicumEO for biofilm dispersion. The population of S. aureus biofilm was approximately reduced by 2 logs after individual treatment of 0.5 mg mL^?1 Helichrysum italicumEO or 400 W CNP. Interestingly, the combined treatment of Helichrysum italicumEO (0.5 mg mL^?1, 40 min) and CNP (400 W, 1 min) reduced the S. aureus viable count in biofilm below 2 logs CFU per cm² after 1‐day storage. Therefore, the synergetic treatment holds great promise to improve the current treatment systems of bacterial contamination on different food‐contact surfaces.     

Detection of Salmonella spp., Yersinia enterocolitica,Listeria monocytogenes and Campylobacter spp. by real‐time multiplex PCR using amplicon DNA melting analysis and probe‐based assay

Syto9 and probe‐based multiplex real‐time PCR assays for simultaneous detection of a group of foodborne pathogens (named SYLC group), targeting Salmonella spp. (invA gene), Yersinia enterocolitica (ystA gene), Listeria monocytogenes (hly gene) and Campylobacter spp. (rrna gene), have been developed. The Syto9 assay generates amplicon DNA melting curve with four peaks of 86.5 ± 0.5, 84 ± 0.5, 81.5 ± 0.5 and 90.5 ± 0.5 °C corresponding Salmonella spp., Y. enterocolitica, L. monocytogenes and Campylobacter spp. targets, respectively. The sensitivities of the Syto9 and TaqMan assays in artificially inoculated chicken wing rinses were in a range of 3.2 × 10² to 3.1 × 10⁴ and 9.8 × 10² to 1.9 × 10⁴ colony‐forming units per millilitre, respectively, depending on the pathogen. All tested target strains (n = 100) were correctly detected by the both assays, whereas nontarget strains (n = 100) demonstrated no cross‐reactivity representing 100% specificity. The assays are suitable for application in qualitative and quantitative detection of SYLC group pathogens in food matrices.