Influence of human gastric juice on oxidation of marine lipids – in vitro study

This study evaluates whether marine lipids can oxidise in acidic stomach environment and whether authentic gastric juice has the potential to act as a pro- or anti-oxidative medium. Oxidation of herring lipids in emulsions and liposomes was followed in in vitro digestion models containing authentic human gastric juice, and compared to models containing hydrochloric acid solution. Peroxide value, concentration of thiobarbituric acid reactive substances and oxygen uptake rate increased in all the models during 2.5 h incubation at pH 4 and 37 °C in darkness. The markers showed no difference between oxidation in gastric juice and hydrochloric acid solution. Gastric juice reduced the prooxidant activity of iron ions measured as oxygen uptake rate, but did not reduce the activity of methemoglobin. Berry juice, green tea, red wine, and caffeic acid reduced oxygen uptake in the acidic environments while coffee, ascorbic acid and orange juice increased oxidation. Beverages accompanying foods containing marine lipids will therefore affect the course of post-prandial lipid oxidation.     

Survival of human norovirus surrogates in milk, orange, and pomegranate juice, and juice blends at refrigeration (4 °C)

Fresh fruits, juices, and beverages have been implicated in human noroviral and hepatitis A virus outbreaks. The purpose of this study was to determine the survival of human norovirus surrogates (murine norovirus, MNV-1; feline calicivirus, FCV-F9; and bacteriophage MS2) in juices (orange and pomegranate juices), juice blends (pomegranate and orange juice) and milk over 0, 1, 2, 7, 14, and 21 days at refrigeration (4 °C). Juices, juice blends, and milk were inoculated with each virus over 21 days, serially diluted in cell culture media, and plaque assayed. MNV-1 showed no reduction in titer after 21 days in orange juice and milk, but moderate reduction (1.4 log) in pomegranate juice from a titer of 5 log(10) PFU/ml. However, MNV-1 was completely reduced after 7 days in the orange and pomegranate juice blend. FCV-F9 from a titer of 6 log(10) PFU/ml was completely reduced after 14 days in orange as well as pomegranate juice and by ～ 3 logs after 21 days in milk at 4 °C. Interestingly, FCV-F9 was completely reduced after 1 day in the orange and pomegranate juice blend at 4 °C. MS2 was reduced by ～ 1.28 log after 21 days in orange juice from a titer of 6 log(10) PFU/ml, and <1 log after 21 days in milk or pomegranate juice, with juice blends showing minimal reduction (<1 log) after 21 days at 4 °C. These results show the survival pattern of noroviruses that aid in the transmission of foodborne viral outbreaks. The data obtained can be used in quantitative viral risk assessment studies and to develop improved measures to prevent virus survival towards controlling outbreaks.     

In vitro and in vivo analysis of fatty acid effects on metabolism of 17β-estradiol and progesterone in dairy cows

Some studies have reported improved reproductive performance with dietary fat supplementation. This study examined effects of fatty acids with different lengths, or desaturation, or both, on metabolism of estradiol (E2) and progesterone (P4) in bovine liver slice incubations (experiments 1 and 2) and in vivo (experiment 3). In experiment 1, effects of fatty acids C16:0 (palmitic acid), C16:1 (palmitoleic acid), C18:1 (oleic acid), and C18:3 (linolenic acid) were evaluated at 30, 100, and 300 μM on P4 and E2 metabolism in vitro. In experiment 2, stearic acid (C18:0) and C18:3 were evaluated in the same incubation conditions. In experiment 1, all of the fatty acids had some significant inhibitory effect on metabolism of P4, E2, or both (300 μM C16:0 on E2; 100 μM C16:1 on E2; 300 μM C16:1 on both P4 and E2; 300 μM C18:1 on P4; and 100 and 300 μM C18:3 on both P4 and E2). In experiment 2, C18:3 (100 and 300 μM) but not C18:0 decreased P4 and E2 metabolism. Overall, the most profound increase (∼60%) in half-life of P4 and E2 was observed with incubations of 300 μM C18:3 in both in vitro experiments. Based on these in vitro results, in experiment 3 linseed oil (rich in C18:3) was supplemented into the abomasum and acute effects on metabolism of E2 and P4 were evaluated. Cows (n = 4) had endogenous E2 and P4 minimized (corpus luteum regressed, follicles aspirated) before receiving continuous intravenous infusion of E2 and P4 to analyze metabolic clearance rate for these hormones during abomasal infusion of saline (control) or 70 mL of linseed oil every 4 h for 28 h. Linseed oil infusion increased C18:3 in plasma by 46%; however, metabolic clearance rate for E2 and P4 were similar for control cows compared with linseed-treated cows. Thus, in vitro experiments indicated that E2 and P4 metabolism can be inhibited by high concentrations of C18:3. Nevertheless, in vivo, linseed oil did not acutely inhibit E2 and P4 metabolism, perhaps because insufficient C18:3 concentrations (increased to ∼8 μM) were achieved. Further research is needed to determine the mechanism(s) of fatty acid inhibition of P4 and E2 metabolism and to discover practical methods to mimic this effect in vivo.     

Fumonisin B1 induced compositional modifications of the renal and hepatic membrane lipids in rats – Dose and exposure time dependence

ABSTRACT

Male Wistar rats were intraperitoneally dosed with fumonisin B1 (FB₁; 0, 20, 50 and 100 mg kg^?1 dietary dose equivalent) for 5 & 10 days to assess dose- and time-dependent effects on renal and hepatic phosphatidylcholine (PC), phosphatidylinositol (PI) and phosphatidylethanolamine (PE) fatty acid (FA) profiles. Renal PC showed increasing FA saturation (SAT) after 5 days; after 10 days polyunsaturation (PUFA) decreased markedly (Σ n3 (total n3), Σ n6, PUFA, unsaturation index (UI) and average FA chain length (ACL)), mostly with linear dose response. In the PI FAs similar changes were observed, decreasing monounsaturated FA, PUFA, UI and ACL (5 & 10 days), while the PE fraction was responsive in Σ n6 (↓) and SAT (↑), but only after 5 days (without dose response for both PI & PE). Liver PC exhibited increasing saturation (C16:0), decreasing polyunsaturation (C20:3 n6 [dihomo-γ-linolenic acid, DGLA]; C20:3 n3); the PI FA profile showed similar alterations after 5 days. PC & PI FA failed to respond in a dose-dependent manner to FB₁. In PE FA profile DGLA decreased, with a decrease of the total n6 FA proportion and dose-dependent increase of n3 FAs. Results revealed expressed renal sensitivity, supporting our earlier published results in terms of oxidative stress and histopathological modifications.     

Evaluation of trigeminal pungency perception of allyl isothiocyanate – A time intensity (TI) study

Allyl isothiocyanate, the primary pungent substance within mustard, horseradish, and wasabi, causes a burning sensation and a lachrymatory effect during consumption. In this time intensity study, the sensory perception of the chemical stimulus allyl isothiocyanate was evaluated in water-based, oil-based, and mustard recipe-based carrier matrices. The results indicate that perceived pungency intensity and time course of perception were both strongly dependent upon allyl isothiocyanate concentration and the composition of the carrier matrices. Increasing allyl isothiocyanate concentrations led to a significant (p < 0.05) increase in maximum intensity of pungency (I_max) in all tested carrier matrices. The intensity of pungency perception for allyl isothiocyanate decreased depending upon the specific matrix used. Specifically, this decrease occurred in the order oil-based carrier < mustard-based carrier < water-based carrier at similar allyl isothiocyanate concentrations. The values for end time of pungency perception (T_End) and duration of decreasing phase (DUR_Dec) indicate that increasing allyl isothiocyanate concentrations prolong the duration of pungency perception. Allyl isothiocyanate was perceived longer in water than in oil- and mustard-based carrier matrices.     

Comparative study on the effects of d-psicose and d-fructose in the Maillard reaction with β-lactoglobulin

d-Psicose, recognized as a noncaloric sweetener, has shown a great potential in food industry. In the present study, d-psicose and d-fructose were used to modify bovine β-lactoglobulin (β-Lg) through Maillard reaction. The Maillard reaction process and the physicochemical and structural properties of the modified proteins were also investigated. The result showed that compared to d-fructose, d-psicose played a more effective role in the Maillard reaction, especially after the initial stage of the reaction. Moreover, the modified β-Lg with d-psicose had more polymeric compounds, higher antioxidant activity, but lower thermal stability than that with d-fructose. These findings, especially the structural changes of the modified proteins, supplied detail information on the Maillard reaction of d-psicose, and could provide some guidance to the practical applications of this rare sugar on food industry.     

In vitro study of anti-oxidative effects of β-carotene and α-lipoic acid for nanocapsulated lipids

In this study we attempted to assess the efficacy of the in vitro activities of β-carotene and α-lipoic acid in conjugation with an encapsulated lipid. Nanoemulsion was prepared and freeze-dried to get nanocapsules. Highest encapsulation efficiency 84.32 ± 1.08% was achieved for α-lipoic acid nanocapsules, whereas for β-carotene nanocapsules it was 79.63 ± 1.41%. Morphology study showed that the dried capsules had an irregular, rough surface. Both anti-oxidants were equally effective in releasing core materials. Complete release of the total lipid occurred within 210 min from both β-carotene and α-lipoic acid bearing nanocapsules. Stability study revealed that β-carotene nanocapsules showed decrease in oil content from 79.63 g lipid to 72.8 g lipid for every 100 g lipid encapsulated, in 3 months, whereas α-lipoic acid nanocapsules retained oil much better, the oil retention being from 84.32 g lipid to 78.08 g lipid per 100 g lipid encapsulated. DPPH radical scavenging activity of β-carotene and α-lipoic acid ranged from 62.75% and 44.13% to 32.94% and 36.95% (after 90 days) respectively. Reducing activity of β-carotene was higher (absorbance 0.492 to 0.291 at 90 days) compared to α-lipoic acid (absorbance 0.243 to 0.109 after 90 days). Again β-carotene and α-lipoic acid metal-chelation activity ranged from 47.65% and 48.59% to 32.315% and 39.29% after 90 days.     

Prevalence and diversity of histamine-forming Lactobacillus parabuchneri strains in raw milk and cheese – A case study

In the present case study, we investigated the causes of consistently elevated histamine content in raw milk cheeses from a Swiss cheese dairy. Screenings of milk samples from 67 farmers revealed that 19.1% of the raw milk samples were contaminated with histamine-forming bacteria. Lactobacillus parabuchneri was detected in 97.4% of contaminated milk samples. The population density of L. parabuchneri was almost always below the limit of quantification of the qPCR method used. Genotyping of 469 isolates provided detailed insight into the diversity of L. parabuchneri in contaminated milks and cheeses. The results of the trace-back study clearly demonstrated that several milk suppliers were responsible for the histamine problem at the cheese dairy under study. Systematic controls of milking systems allowed persistent contamination sources of L. parabuchneri at the farm level to be identified and eliminated and thereby to reduce the percentage of contaminated milks to 8.5% within the study period.     

Manipulating effects of fruits and vegetables on gut microbiota – a critical review

The objective of the current review was to systematically investigate health-promoting manipulating effects of fruits and vegetables (F&V) on the gut microbiota. The function of gut microbes was found to promote health effects in the host by scavenging free radicals, modulating immune system, alleviating obesity and diabetes. Masters that manipulate the gut microbiota are the phytochemicals within specific types of F&V, where polyphenols account for the largest proportion, along with alkaloids, terpenes, nitrogen-containing compounds, polysaccharides and natural pigments present in plants. These bioactive compounds exhibit the regulative influences on gut microorganisms characterised by rescuing dysbiosis of gut microbiota, increasing/decreasing microbial abundance, restructuring microbial composition, and rebalancing gut microbial homeostasis. This review indicated that F&V extracts targeting at gut microbiota could be a new scope of ingredient selection in the field of functional food especially for amelioration of dysfunction of intestinal ecosystem.     

Thermal inactivation of lactoperoxidase in goat,sheep and bovine milk – A comparative kinetic and thermodynamic study

Using isothermal heating, inactivation of lactoperoxidase (LPO) in goat, sheep and cow milk was studied in the temperature range of 70–77 °C. Kinetic and thermodynamics studies were carried out at different time–temperature combination in order to evaluate the suitability of LPO as marker for the heat-treatment of milk and dairy products from different species. The thermal inactivation of LPO followed the first-order kinetics. D- and k-values decreased and increased, respectively with increasing temperature, indicating a more rapid LPO inactivation at higher temperatures. The influence of temperature on the inactivation rate constant was quantified using the Arrhenius and thermal death time models. The corresponding z-values were 3.38 ± 0.013, 4.11 ± 0.24 and 3.58 ± 0.004 °C in goat, sheep and cow milk, respectively. Activation energy values varied between milk species with 678.96 ± 21.43 kJ mol⁻¹ in goat milk, 560.87 ± 28.18 kJ mol⁻¹ in sheep milk and 641.56 ± 13.12 kJ mol⁻¹ in cow milk, respectively.     

Polymeric proanthocyanidins in skins and seeds of 37 Vitis vinifera L. cultivars: a methodological comparative study

Abstract: The polymeric proanthocyanidins (PAs) composition of skins and seeds from different Vitis vinifera L. cv. was evaluated, sampling 37 cultivar, preserved in the grapevine collection of Grinzane Cavour (Piedmont, Italy). PAs were quantified using both spectrophotometric (n‐butanol and vanillin assay) and chromatographic (high‐performance liquid chromatography [HPLC]) methods, and the evaluation of their antioxidant activity was performed using the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) scavenging assay. Results of PAs quantification with the different methods were significantly correlated. A strong correlation pointed out between anthocyans and PAs content (particularly regarding HPLC method; r = 0.9359, P = 0), and the antioxidant activity was not dependent on the polymeric PAs content, but negatively correlated with the degree of polymerization (r =–0.6102, P = 1 × 10^?4). The hierarchical clustering on principal components analysis allowed grouping the samples in 3 different clusters, observing a direct association between the cluster classification and the anthocyans/PAs content.     

Synergistic effect of high-intensity ultrasound and β-cyclodextrin treatments on browning control in apple juice

This work evaluated the synergistic effects of combined high-intensity ultrasound (HIU) with β-cyclodextrin (β-CD) treatments on inhibiting browning of apple juice and explored the mechanism through simulation system. The combined treatment of 300 W HIU with 0.006 g mL⁻¹ β-CD had a synergistic impact on maintaining juice colour, resulting in a 39.06% reduction in browning degree, only a 36.64% decrease in total phenolic content, and a 17.82% reduction in PPO activity. The inhibition of enzymatic browning in simulated system revealed that HIU suppressed the enzyme (Polyphenol oxidase, PPO) and β-CD inhibited enzyme (PPO) and embedded substrate (polyphenol). The results of spectroscopic analysis showed that the particle-size distribution of PPO narrowed, the content of α-helix in the secondary structure increased, the fluorescence intensity increased, and the maximum wavelength was red-shifted after HIU and β-CD treatment. Changes in structure could further result in PPO activity loss. Hence, the combined treatment could synthetically alleviate the browning of apple juice.     

Effects of genetic variants and sialylation on in vitro digestibility of purified κ-casein

Milk with different κ-casein (CN) phenotypes has previously been found to influence its gastric digestion rate. Therefore, the aim of the present study is to disentangle contributions of genetic variation and its related sialylation on the in vitro digestion process of κ-CN. Accordingly, κ-CN was purified from milk representing homozygous cows with κ-CN phenotypes AA, BB, or EE and used as substrate molecules in model studies using the INFOGEST 2.0 in vitro static digestion model. Furthermore, the effect of removal of the terminal sialic acids present on the O-linked oligosaccharides of the purified κ-CN A, B, and E protein variants were studied by desialylation enzymatic assays. The κ-CN proteins were purified by reducing anion exchange chromatography with purities of variants A, B, and E of 93.0, 97.1, and 90.0%, respectively. Protein degradations of native and desialylated κ-CN isolates in gastric and intestinal phases were investigated by sodium dodecyl sulfate-PAGE, degree of hydrolysis (DH), and liquid chromatography electrospray ionization mass spectrometry. It was shown that after purification, the κ-CN molecules reassembled into multimer states, which then constituted the basis for the digestion studies. As assessed by DH, purified variants A and E were found to exhibit faster in vitro digestion rates in both gastric and intestinal phases compared with variant B. Desialylation increased both gastric and intestinal digestion rates for all variants, as measured by DH. In the gastric phase, desialylation promoted digestion of variant B at a rate comparable with native variants A and E, whereas in the intestinal phase, desialylation of variant B promoted better digestion than native A or E. Taken together, the results confirm that low glycosylation degree of purified κ-CN promotes faster in vitro digestion rates, and that desialylation of the O-linked oligosaccharides further promotes digestion. This finding could be applied to produce dairy products with enhanced digestibility.     

Unraveling the nature of ohmic heating effects in structural aspects of whey proteins – The impact of electrical and electrochemical effects

Electric field (EF) variables and electrode material are fundamental factors in ohmic heating (OH) processing. In this study, stainless steel, titanium and graphite were used as electrodes in conventional and OH (at 50 Hz and 20 kHz) treatments of whey protein isolate solutions at pH 3 and pH 7. The treated solutions were characterized in terms of UV absorbance, changes in intrinsic fluorescence, binding of a conformational probe and secondary structure (evaluated by circular dichroism). Differentiated structural features were induced by the different treatment conditions and were more evident at pH 7 and OH at 50 Hz. The metal leakage (quantified with ICP-MS) from the electrodes revealed to influence the equilibrium of early stages of protein aggregation, with stainless steel demonstrating to be the most electro-active material followed by titanium and finally graphite (that did not release metal). These findings highlight that structural properties of whey proteins may not only be influenced by the EF action but also by the leakage of metals from the electrodes.Industrial relevanceOH is a recognized emerging processing technology and has a recognized potential to control and enhance protein functionality due its ability to influence protein structural features. Both electrode stability and protein structural changes are related with the EF operational parameters such as voltage, current or frequency. These parameters are decisive in the occurrence and extension of electrochemical phenomena and in the EF action mechanisms over protein structure. The confirmation of EF non-thermal effects at high and low frequencies (independently of the electrochemical phenomena) dissipated previous doubts regarding its effectiveness to modulate protein functionality. The understanding of the electrode material stability and influence of different electric parameters on the product's functionality, stability and safety are fundamental to design OH devices and to the establishment of operational protocols. The stability and material release from the electrodes is a fundamental factor during OH processing, imposing serious implications in equipment costs, maintenance, as well as in product quality and safety. This study highlights the influence of different electrode materials during OH at different electrical frequencies and its impacts on protein structural aspects.     

Immune-enhancing effects of β-lactoglobulin glycated with lactose following in vitro digestion on cyclophosphamide-induced immunosuppressed mice

β-Lactoglobulin (β-LG) is a major milk protein, making up more than 53% of the total whey proteins, and is seen as a valuable ingredient in food processing because of its high essential amino acid content and diverse functional applications. The Maillard reaction can occur during the storage and processing of food and generate various beneficial effects, including anti-allergenicity, antioxidant, and immunomodulatory effects. The addition of an β-LG-lactose conjugate (LGL) produced by the Maillard reaction was shown to have a strong immune-enhancing effect, increasing both nitric oxide generation and cytokine expression through activation of RAW 264.7 cells, even after in vitro digestion. Furthermore, daily LGL administration resulted in the upregulation of several immune markers in a cyclophosphamide-induced immunosuppressive mouse model, indicating that this treatment stimulates multiple immune cells, including macrophages, natural killer cells, and lymphocytes, enhancing the proliferation and activation of both the innate and adaptive immune responses. Taken together, these findings indicate that consuming LGL on a regular basis can improve immunity by increasing the natural production of various immune cells.     

A comparative study of the effects of three galactomannans on the functionality of extruded pea–rice blends

The present study evaluated the effects of three galactomannans on the physical and nutritional characteristics, and sensory acceptability of pea–rice based extruded products, targeted as nutritional snacks. A base blend of 70:30 pea and rice fortified with guar gum (GG), locust bean gum (LBG) and fenugreek gum (FG), at 5%, 10%, 15% and 20%, was extruded at pre-determined optimum processing conditions. All three gums resulted in good expanded products. Increasing the inclusion levels of gums, however, had no effect (P > 0.05) on the degree of expansion. Addition of 5% GG and LBG reduced (P < 0.05) the hardness, while the inclusion of GG and LBG at levels higher than 5%, and all inclusion levels of FG, increased (P < 0.05) the hardness of extruded products. Relative to other treatments, FG produced extrudates that were harder and crispier. The mean scores of sensory evaluation indicated that all products containing gums up to 15% were within the acceptable range. Extrusion increased (P < 0.001) the soluble fibre content and decreased the insoluble fraction; the magnitude of these changes were greater in GG and FG. The addition of 15% gums in the pea–rice blend reduced (P < 0.05) the glycaemic index to less than 55. Overall, the data suggest that all three galactomannans could be incorporated up to 15% in a pea–rice blend to develop nutritious, organoleptically acceptable, extruded snack products with low glycaemic index.     

Effect of temperature and substrate on Pef inactivation of Lactobacillus plantarum in an orange juice–milk beverage

The inactivation kinetics of Lactobacillus plantarum in an orange juice–milk beverage treated by Pulsed Electric Fields (PEF) were studied. Experimental data were fitted to Bigelow and Hülsheger kinetic models and Weibull frequency distribution function. Results indicate that both Hülsheger model and Weibull function fit well the experimental data being Accuracy factor values (Af) closer to 1 and Mean Square Error (MSE) closer to 0. The parameter of the Weibull model can be considered as a kinetic indicator as it expresses the microorganism's resistance to treatment by electric pulses. An increase in temperature favoured the inactivation of L. plantarum by PEF as reflected by a decreased in value. Under the same conditions to those studied by other authors we reached less inactivation of L. plantarum in the beverage used in this study than in substrates with a simpler composition.     

Design factors influence consumers’ gazing behaviour and decision time in an eye-tracking test: A study on food images

The eye-tracking method has been increasingly used for studying consumer behaviour over the last few years. Understanding factors influencing consumers’ gazing behaviour in an eye-tracking test will contribute to a better organisation and a more valid application of the method. The aim of this work is to study how test design influences gazing behaviour and decision time of food consumers in an eye-tracking test. Three factors of the test design were investigated: (1) Number of images in one testing picture (two, three, four, five, and six images/picture); (2) content of question (tastiness, healthiness, price, convenience, and familiarity); and (3) type of evaluation (maximum choice, minimum choice, ranking, rating, and grouping). Two experiments were conducted. In the first experiment, performed with 100 participants, the influence of individual factors was studied. In the second experiment, performed with 64 participants, the joint effects (interactions) of the tested factors were investigated. The results showed that gazing behaviour and decision time are strongly influenced by the type of evaluation and the number of images, but not by the content of question. No joint effect of influencing factors (number of images and type of evaluation) was found. Findings are discussed in considering the relationship between eye-movements, cognitive goals, and tasks. This study highlights the importance of understanding factors influencing gazing behaviour and decision time in an eye-tracking test.     

Effect of chitosan-based solutions applied as edible coatings and water glazing on frozen salmon preservation – A pilot-scale study

The aim of this research was to compare the effect of chitosan solutions on frozen salmon preservation with that of water glazing. For this purpose, three chitosan solutions (0.25%, 0.50% and 0.75% w/v) and water were applied in different amounts (6%, 8% and 11% of coated fillet weight) directly on the surface of frozen salmon. In order to accelerate the deterioration processes, salmon was stored during 14 weeks at −5 °C. Microbial and chemical indices were used to assess deterioration during storage and the coating stability was evaluated through weight loss measurements. The results obtained showed that chitosan coatings can be a good barrier to protect frozen fish from deterioration. Microbial growth, assessed by total viable counts (TVC), and total volatile basic nitrogen (TVB-N) were maintained below the maximum limits recommended which are 5 × 105 CFU/g and 35 mg nitrogen/100 g fish, respectively. The use of 0.50% and 0.75% chitosan solutions generally demonstrated to be more efficient in preventing salmon weight loss.