Effect Of Food Structure Research Articles

Effect of food structure and buffering capacity on pathogen survival during in vitro digestion

Even though a plethora of barriers are employed by the human gastrointestinal tract (GIT) to cope with invading pathogens, foodborne diseases are still a common problem. The survival of food pathogens in the GIT is known to depend on food carrier properties. The aim of this study was to investigate the influence of food buffering capacity and food structure on the survival of Salmonella Typhimurium and Listeria monocytogenes during simulated digestion, following contamination of different food model systems that had different combinations of fat and protein content. The results illustrated the strong protective properties of proteins, acting either as a strong buffering agent or as a physical barrier against gastric acidity, for both pathogens. In comparison, fat manifested a lower buffering capacity and weaker protective effects against the two pathogens. Intriguingly, a low fat content was often linked with increased microbial resistance. Nonetheless, both pathogens survived their transit through the simulated GIT in all cases, with S. Typhimurium exhibiting growth during intestinal digestion and L.monocytogenes demonstrating a healthy residual population at the end of the intestinal phase. These results corroborate the need for a deeper understanding regarding the mechanisms with which food affects bacterial survival in the human GIT.

Carvacrol release from PLA to a model food emulsion: Impact of oil droplet size

The effect of food structure on the release of a volatile antimicrobial from an active packaging (AP) was investigated by measuring the migration of carvacrol from a polylactic acid (PLA) film to a model food system, namely, an oil-in-water (O/W) emulsion. We aimed to understand the influence of the oil droplet size on the kinetics of carvacrol migration from the PLA film to the emulsions, on its final partitioning and antimicrobial activity. Five model systems were prepared: they had the same composition, i.e., an oil fraction of 20 wt% and an aqueous phase containing 1.5 wt % whey protein isolate, but different structures.Emulsions with the smallest oil droplets (d3,2 = 0.27 μm) absorbed a higher amount of carvacrol than emulsions with large oil droplets (d3,2 = 0.34 μm and d3,2 = 0.51 μm). Despite the higher overall carvacrol concentration, inhibition of bacterial growth was less effective in emulsions with the smallest droplet (d3,2 = 0.27 μm). This can be explained by the highest log K of carvacrol in this emulsion indicating that carvacrol partitioned more into the oil droplet phase than in the continuous phase.The current study suggests that the spatial distribution of carvacrol in the emulsion determines its actual antimicrobial effect. The combined findings of antimicrobial distribution and activity highlight the need for tailoring active packaging systems based on the physical characteristics of multiphase food matrices.

Effect of Food Structure, Water Activity, and Long-Term Storage on X-Ray Irradiation for Inactivating Salmonella Enteritidis PT30 in Low-Moisture Foods

Recent outbreaks and recalls of low-moisture foods contaminated with Salmonella have been recognized as a major public health risk that demands the development of new Salmonella mitigation strategies and technologies. This study aimed to assess the efficacy of X-ray irradiation for inactivating Salmonella on or in almonds (kernels, meal, butter), dates (whole fruit, paste), and wheat (kernels, flour) at various water activities (aw) and storage periods. The raw materials were inoculated with Salmonella Enteritidis PT30, conditioned to 0.25, 0.45, and 0.65 aw in a humidity-controlled chamber, processed to various fabricated products, and reconditioned to the desired aw before treatment. In a storage study, inoculated almond kernels were stored in sealed tin cans for 7, 15, 27, and 103 weeks, irradiated with X ray (0.5 to 11 kGy, targeting up to a ∼2.5-log reduction) at the end of each storage period, and plated for Salmonella survivors to determine the efficacy of irradiation in terms of D10-value (dose required to reduce 90% of the population). Salmonella was least resistant (D10-value = 0.378 kGy) on the surface of almond kernels at 0.25 aw and most resistant (D10-value = 2.34 kGy) on the surface of dates at 0.45 aw. The Salmonella D10-value was 61% lower in date paste than on whole date fruit. Storage of almonds generally had no effect on the irradiation resistance of Salmonella over 103 weeks. Overall, these results indicate that product structure (whole, meals, powder, or paste), water activity (0.25 to 0.65 aw), and storage period (0 to 103 weeks) should be considered when determining the efficacy of X-ray irradiation for inactivating Salmonella in various low-water-activity foods.

Effect of Food Structure and Processing on (Poly)phenol-Gut Microbiota Interactions and the Effects on Human Health.

The two-way interaction of food (poly)phenols with the human gut microbiota has been studied throughout the past ten years. Research has shown that this interaction can be relevant to explain the health effects of these phytochemicals. The effect of the food matrix and food processing on this interaction has only been partially studied. In this article, the studies within this field have been critically reviewed, with a special focus on the following groups of phenolic metabolites: citrus flavanones, pomegranate ellagitannins, and cocoa proanthocyanidins. The available research shows that both the food matrix and food processing can be relevant factors for gut microbiota reshaping to reach a healthier microbial ecology and for the conversion of polyphenols to bioactive and bioavailable metabolites. There are, however, some research gaps that indicate a more comprehensive research approach is needed to reach valid conclusions regarding the gut microbiota-mediated effects of polyphenols on human health.

The degree of processing of foods which are most widely consumed by the French elderly population is associated with satiety and glycemic potentials and nutrient profiles.

Food processing impacts both food structure and nutritional density. The effect of food structure on satiety and glycemic potentials is well recognized. However, the association between processing, satiety and glycemic potentials and nutrient profiles has not been much studied, especially in the diets of the elderly. Therefore, this study aimed at exploring relations between the level of food processing, consumption and nutrient profiles and satiety and glycemic potentials among 6686 French elderly people (≥65 years). Dietary assessment was realized through a web-based 24 h dietary record tool. Among a total of 2688 foods, 280 generic foods were aggregated based on a consumption threshold of at least 5% by the population. The satiety potential was calculated using the Fullness Factor equation, and the glycemic potential using the glycemic index and the glucose glycemic equivalent. Foods and dishes were ranked according to an adapted international NOVA classification as raw/minimally-processed (G1), processed (G2) and ultra-processed (G3). ANOVA and correlation analyses showed that the more food is processed, the lower its satiety potential and nutrient density and the higher its glycemic impact, especially when comparing G1 and G3. Besides, the foods consumed in the greatest quantity daily tend to be the most satiating, and ultra-processed foods were among the less frequently consumed both in terms of percentage and daily quantity (around two-fold difference between minimally- and ultra-processed foods). In conclusion, because it is partly related to health food potential, the degree of processing, especially for ultra-processed products, should be taken into consideration more when evaluating consumption profiles of different populations.

The effect of medium structure complexity on the growth of Saccharomyces cerevisiae in gelatin–dextran systems

As most food systems are (semi-)solid, the effect of food structure on bacterial growth has been widely acknowledged. However, studies on the growth dynamics of yeasts have neglected the effect of food structure.In this paper, the growth dynamics of the spoilage yeast Saccharomyces cerevisiae was investigated at 23.5°C in broth, singular, homogeneous biopolymer systems and binary biopolymer systems with a heterogeneous microstructure. The biopolymers gelatin and dextran were used to introduce the different levels of structure. The metabolizing ability of gelatin and dextran by S. cerevisiae was examined. To study microbial behavior in the binary systems at the micro level, mixtures were imaged with confocal laser scanning microscopy (CLSM). Growth dynamics and microscopic images of S. cerevisiae were compared with those obtained for Escherichia coli in the same model system (Boons et al., 2014). Different phase-separated, heterogeneous microstructures were obtained by changing the amount of added gelatin and dextran. Regardless of the microstructure, S. cerevisiae was preferentially located in the dextran phase. Metabolizing ability-tests indicated that gelatin could be consumed by S. cerevisiae but in the presence of glucose, no change in gelatin concentration was observed. No indication of dextran metabolizing ability was observed. When supplementing broth with gelatin or dextran alone, an enhanced growth rate and maximum cell density were observed. This enhancement was further increased by adding a second biopolymer, introducing a heterogeneous microstructure and hence increasing the medium structure complexity.The results obtained indicate that food structure complexity plays a significant role in the growth dynamics of S. cerevisiae, an important food spoiler.

Rye kernel breakfast increases satiety in the afternoon - an effect of food structure

BackgroundThe structure of whole grain cereals is maintained to varying degrees during processing and preparation of foods. Food structure can influence metabolism, including perceived hunger and satiety. A diet that enhances satiety per calorie may help to prevent excessive calorie intake. The objective of this work was to compare subjective appetite ratings after consumption of intact and milled rye kernels.MethodsTwo studies were performed using a randomized, cross-over design. Ratings for appetite (hunger, satiety and desire to eat) were registered during an 8-h period after consumption of whole and milled rye kernels prepared as breads (study 1, n = 24) and porridges (study 2, n = 20). Sifted wheat bread was used as reference in both study parts and the products were eaten in iso-caloric portions with standardized additional breakfast foods. Breads and porridges were analyzed to determine whether structure (whole vs. milled kernels) effected dietary fibre content and composition after preparation of the products. Statistical evaluation of the appetite ratings after intake of the different breakfasts was done by paired t-tests for morning and afternoon ratings separately, with subjects as random effect and type of breakfast and time points as fixed effects.ResultsAll rye breakfasts resulted in higher satiety ratings in the morning and afternoon compared with the iso-caloric reference breakfast with sifted wheat bread. Rye bread with milled or whole kernels affected appetite equally, so no effect of structure was observed. In contrast, after consumption of the rye kernel breakfast, satiety was increased and hunger suppressed in the afternoon compared with the milled rye kernel porridge breakfast. This effect could be related to structural differences alone, because the products were equal in nutritional content including dietary fibre content and composition.ConclusionsThe study demonstrates that small changes in diet composition such as cereal grain structure have the potential to effect feelings of hunger and satiety.Trial registrationThis trial was registered at clinicaltrials.gov as NCT01042418.

Understanding flavour quality: Difficult or impossible?

Flavour arises from a complex series of events, starting with genetic and environmental influences on the composition of the food material, and leading via processing changes and chemoreception to the consumer's perception of flavour. Three areas in flavour research seem to be most likely to repay new work. The first is flavour release, that is what happens in the mouth, the effect of food structure, and what happens when food is eaten. Secondly, there are good opportunities for progress in studies of chemoreceptor mechanisms, and thirdly neural networks offer the hope of solving some of the more intractable mathematical modelling problems.