Journal: Food research international (Ottawa, Ont.)
There is a growing body of evidence implicating the gut ‘microbiome’ role in overall human health. Bacterial species belonging to the genera Lactobacillus and Bifidobacterium are generally considered to be beneficial and are commonly used in probiotic applications, whereas increases in some genera including Clostridum, Eubacterium and Bacteroides are implicated in negative health outcomes. Dietary polyphenols are bioactive compounds that have been found to increase the numbers of beneficial bacteria and antimicrobial actions against pathogenic bacteria, however most studies have been conducted in animal models or in-vitro colonic models. The aim of this systematic review was to provide an overview of recent trials on the effect of dietary grape and red wine polyphenols on the gut microbiota in humans. Following PRISMA guidelines, a systematic review was conducted of electronic databases (PubMed, CINAHL, Cochrane Library, Wed of Science and Scopus) to identify human intervention trials examining the effect of grape or wine polyphenols on gut microbiota. Seven trials met the inclusion criteria. One study looked at changes in gut microbiota following the ingestion of de-alcoholised red wine or red wine, and six studies referred to gut microbiota as intermediates in formation of phenolic metabolites. All studies confirmed that ingested polyphenols from grape and red wine, were modulated by gut microbiota, increasing numbers of polyphenolic metabolites which were found in blood, urine, ileal fluid and faeces. Intake of polyphenols derived from grape and red wine can modulate gut microbiota and contribute to beneficial microbial ecology that can enhance human health benefits. Additionally, grape and red wine polyphenols were modulated by the gut microbiota and there is a potential for a two-way relationship between the gut microbiota and polyphenolic compounds. Nevertheless, additional research is required to fully understand the complex relationship between gut microbiota and dietary polyphenols before any health claims can be made in relation to human health.
This study evaluates the effect of modified lecithin (ML) and sodium caseinate (SC) on the formulation, stability and bioaccessibility of astaxanthin (AXT) loaded oil-in-water (O/W) nanoemulsions. These nanoemulsions were formulated using high-pressure homogenization in four passes at 100MPa. The volume mean diameter (d4,3) of nanoemulsions produced by ML and SC were 163±5 and 144±12 nm, respectively. The physiochemical stability of nanoemulsions was recorded at 25°C. The nanoemulsions prepared by ML were stable for 30 minutes against a wide range of pH and heating temperatures (60-120 °C). However, ML-stabilized nanoemulsions showed droplet growth when treated at high NaCl concentrations. In comparison, droplet growth was observed in SC-stabilized nanoemulsions at pH4 and at high temperature treatment. However, SC-stabilized nanoemulsions were stable at high NaCl concentration (500 mM). The SC-stabilized nanoemulsions showed good physical and chemical stability (>70%) after 30 days of storage. The bioaccessibility of AXT in nanoemulsions was significantly higher in ML (33%) than in SC-stabilized nanoemulsions (6%), indicating a strong influence of emulsifier on bioaccessibility. These findings provide valuable information in designing nutritional products such as aqueous based AXT fortified beverages.
Milk protein concentrate (MPC) powders are increasingly utilized in manufacturing of protein fortified beverages. Thermal stability of the protein dispersions is of significant importance in such applications. It is known that a decrease in pH can induce partial dissociation of casein micelles and modify the natural equilibrium of calcium and phosphate between the micelles and the serum phase. The presence of soluble casein may improve the rehydration properties of MPC powders, and may impact their thermal stability. The objective of this work was to investigate the effects of partial acidification of milk prior to ultrafiltration on the heat stability of reconstituted MPC dispersions. Milk protein concentrate powders were prepared from skim milk acidified to pH6.0 by addition of glucono-δ-lactone, and then concentrated using ultrafiltration (UF) and diafiltration (DF). The heat stability of the reconstituted MPC dispersions was studied, by determining heat coagulation time, particle size, turbidity, viscosity, soluble and colloidal calcium and phosphate, and non-sedimentable casein both before and after heating at 120°C. Reconstituted MPC powders made with partially acidified skim milk contained lower soluble calcium and phosphate and exhibited very poor thermal stability compared to MPC powders made with skim milk at its natural pH. The thermal stability of the acidified MPC dispersions was not only recovered by restoration of pH and the serum composition through dialysis against skim milk, but it was improved compared to control MPC dispersions. All dialyzed samples had comparable pH, protein content and calcium and phosphate concentration, but the structure of the casein micelles was altered, causing differences in the type of soluble aggregates. It was concluded that the integrity of the casein micelles and the amount of dissociated, non-sedimentable caseins play a major role in determining the thermal stability of the MPC dispersions.
Elemental sulfur is a fungicide traditionally used to control Powdery Mildew in the production of grapes. The presence of sulfur residues in grape juice has been associated with increased production of hydrogen sulfide during fermentation, which could take part in the formation of the varietal thiol 3-mercaptohexanol. This work examines whether elemental sulfur additions to Sauvignon blanc juice can increase the levels of sought-after varietal thiols. Initial trials were performed in South Africa and indicated a positive impact of sulfur on the levels of thiols. Further experiments were then carried out with New Zealand Sauvignon blanc and confirmed a positive relationship between elemental sulfur additions and wine varietal thiols. The formation of hydrogen sulfide was observed when the addition of elemental sulfur was made to clarified juice, along with an increase in further reductive sulfur compounds. When the addition of sulfur was made to pressed juice, prior to clarification, the production of reductive sulfur compounds was drastically decreased. Some mechanistic considerations are also presented, involving the reduction of sulfur to hydrogen sulfide prior to fermentation.
The objective of this work was characterize and evaluate the protein-stabilizing property of pea soluble polysaccharide (PSPS) extracted from pea by-products using spray-drying and ethanol precipitation oven drying, obtaining PSPS-A and PSPS-B, respectively. The weight average molecular weight (Mw) of PSPS-A and PSPS-B were 625 kDa and 809 kDa, respectively. The results of Fourier transform infrared spectroscopy (FT-IR) analysis indicated that PSPS-A, PSPS-B and soybean soluble polysaccharide (SSPS) contained the same functional groups. The absolute negative charges of PSPS-A or PSPS-B in aqueous solution were slightly higher than that of SSPS at pH 2.0 to 7.0. The apparent diameter of PSPS-B (479.1 nm) was larger than that of PSPS-A (127.7 nm) and SSPS (209.5 nm) were measured by dynamic light scattering. The AFM images revealed that both PSPS-A and PSPS-B possessed star-like structures with more side chains as compared to SSPS. It was found that the addition of 0.15% PSPS-A or 0.1% PSPS-B was adequate to prevent the aggregation of protein and obtain stable dispersion. Furthermore, PSPS has a wider pH range (pH 3.6-4.6) to stabilize milk protein than SSPS (pH 3.6-4.2).
Taste and aroma compounds in Tianyou were determined using HPLC and GC-MS/GC-olfactometry. By comparison with light soy sauce (control), the contents of salt, sugar, total nitrogen and total acid in Tianyou were higher, while the contents of umami, sweet and bitter free amino acids, and the percentage of 1-5kDa peptides in Tianyou were lower. Thirty-one aroma-active compounds were identified in both Tianyou and the control (30 compounds in common). Aroma extraction dilution analysis indicated that most flavor dilution factors of aroma-active compounds were lower in Tianyou than the control. Quantitative descriptive analysis showed that Tianyou had significantly stronger salty and sweet tastes, weaker umami taste and weaker malty, caramel-like and smoky notes when compared to the control (p<0.05), which were in agreement with the analyses of taste and aroma compounds. This confirms that Tianyou has a distinctively different flavor from light soy sauce.
Traditional Mediterranean plant-based dishes could allow tackling malnutrition while preserving the cultural heritage. To determine the effect of the cooking method on mineral bioavailability, the content in minerals and chelators of Mloukhiya, a Mediterranean dish based on jute leaves (Corchorus olitorius) that contains also meat, was monitored during the whole cooking process. Mineral bioaccessibility was assessed by measuring in vitro dialyzability. Model equation was also used to estimate mineral bioavailability. Comparison of Mloukhiya samples collected at different cooking time points showed that the dish total mineral content did not change despite the exchanges between sauce and meat during cooking. However, iron bioavailability decreased, because 58% of heme iron was degraded after 5h of cooking and non-heme iron showed poor bioaccessibility (1.2%), mainly due to its high content of phenolic compounds. The bioaccessibility of other minerals (zinc, calcium, magnesium and potassium) was high, indicating that the food matrix had no or little effect. The mineral bioavailability values predicted by using mathematical models were of the same order of magnitude as the bioaccessibility values.
Black soldier fly (BSF, Hermetia illucens) constitutes an economic way to convert residual biomasses into a valuable source of biomolecules, such as proteins, lipids and chitin. The present investigation was undertaken to evaluate the feasibility of applying different extraction protocols, either chemical extractions or enzymatic assisted extraction, to recover pure fat, protein and chitin fractions. First, exact proximate composition, total amino acids, fatty acids profile, and N-acetylglucosamine content of the prepupae samples were determined. BSF prepupae biomass contained, expressed on dry weight, 32% proteins, 37% lipids, 19% minerals, 9% chitin. The lipid fraction was easily recovered by organic solvents, while the most challenging issue was the separation of protein from chitin. The best separation was obtained by alkali extraction of proteins (96% of protein recovered) albeit with loss in their integrity as indicated by the measurement of the degree of hydrolysis with the o-phthaldialdehyde method. To avoid protein damage in alkali media, a stepwise protein extraction adopting milder conditions was also explored based on Osborne fractionation method, allowing the recovery of >85% of BSF high purity and high quality proteins, and the obtainment of chitin-enriched fraction as well. The possibility of using an enzymatic assisted extraction of proteins was also explored, obtaining a maximum nitrogen solubilisation in the best case (with Bacillus licheniformis protease) of about 60%. In this latter case, the chitin fraction obtained also had a significant residual protein content.
In recent years there has been a growing interest in the potential benefits and new applications that may be afforded by incorporating digital flavour augmentation technologies into traditional eating and drinking experiences. Although many studies have shown how controlled olfactory, visual and auditory cues can impact flavour experiences, there has been a relatively small amount of work that has investigated the utilisation of digital gustatory (taste) augmentation in the same context. Hence, we have created two utensils, a pair of chopsticks and a soup bowl, that apply controlled electrical pulses to the tip of the tongue during consumption in order to augment flavours through electrical stimulation. As such, in this paper we present a study that aimed to evaluate the impact of electric taste augmentation on two types of eating experiences: consuming mashed potato and miso soup. Based on this study, our findings demonstrate that 1) significant increases in perceived saltiness and sourness can be achieved when consuming unsalted mashed potato and 2) significantly higher ratings of sourness can be achieved when consuming diluted miso soup.
This study evaluates life cycle environmental impacts associated with chocolate products made and consumed in the UK. The paper focuses on three representative chocolate products occupying 90% of the market: ‘moulded chocolate’, ‘chocolate countlines’ and ‘chocolates in bag’. The impacts were estimated using life cycle assessment (LCA) as a tool and following the ReCiPe impact assessment method. The water footprint was also considered. For example, the global warming potential ranges between 2.91 and 4.15 kg CO2eq., primary energy demand from 30 to 41 MJ and the water footprint, including water stress, from 31 to 63 l per kilogram of chocolate. The raw materials are the major hotspot across all impact categories for all three product types, followed by the chocolate production process and packaging. The raw material impacts are mainly due to milk powder, cocoa derivatives, sugar and palm oil. The sensitivity analysis shows that the results for global warming potential are sensitive to land-use change (LUC) associated with cocoa production, increasing the impact of the chocolate products by three to four times if LUC is involved. The improvement opportunities targeting the key contributing stages suggest that GWP of chocolates could be reduced by 14%-19%. Chocolate countlines have the highest contribution to the total impacts at the UK level (37%-43%), followed by chocolates in bag (28%-33%). Moulded chocolates and other chocolate confectionary make up the rest of the impacts, with a roughly equal share each. Chocolate consumption in the UK contributes 4.7% to the primary energy consumption and 2.4% to the GHG emissions from the whole food and drink sector. The results of this work will be of interest to policy makers, chocolate producers and consumers, helping them to make more informed decisions towards sustainable production and consumption of chocolate products.