Effect Of Food Matrix Research Articles

Effect of food matrix on amandin, almond ( Prunus dulcis L.) major protein, immunorecognition and recovery

Amandin, the primary storage protein in almonds, contains key polypeptides recognized by almond-allergic patients. A variety of food matrices representing diverse categories of foods were analyzed to assess the effect of food matrix on amandin recognition and recovery using rabbit polyclonal antibody based immunoassays. Food matrices from dairy, nuts, and vegetables typically resulted in over-estimation of amandin. Some foods representing legumes and cereals resulted in over-estimation while others in under-estimation of amandin. The amandin recovery range was 116–198 μg/100μg (dairy) 110–292 μg/100μg (tree nuts), 43–304 μg/100μg (legumes), 106–183 μg/100μg (most cereals- with the exception of barley, whole-wheat flour, wild rice and raisin bran whole mix). Amandin recovery from spices was typically low (2–85 μg/100μg) with a few exceptions where higher recoveries were observed (121–334 μg/100μg). Salt (black and white), tea, confectionery (sugar, cocoa, dark chocolate), and fruits (1–83 μg/100μg) generally resulted in lower recoveries. Tested food matrices did not adversely affect amandin immunorecognition in Western blots. The pH and the extraction buffer type affected amandin recovery. The results suggest that food matrix effects as well as extraction conditions need to be carefully evaluated when developing immunoassays for amandin detection and quantification.

Red wine metabolites modulate NF-κB, activator protein-1 and cAMP response element-binding proteins in human endothelial cells

We have studied the effect of human serum, collected after red wine consumption (RWS), on TNF-alpha-dependent activation of transcription factors (NF-kappaB, activator protein-1 (AP-1) and cAMP response element-binding proteins) and on the expression of selected genes involved in cell adhesion or fibrinolysis processes in human primary endothelial cells (human umbilical vein endothelial cells (HUVEC)). Our data indicate that RWS containing RW metabolites, isolated after 40 min from an acute consume of wine (5 ml/kg body weight), induces nuclear translocation of NF-kappaB and AP-1 in the absence of any further stimulus. On the other hand, TNF-alpha treatment in the presence of RWS is associated with a delay in transcription factor activation and to a negative modulation on the expression of specific genes. Moreover, RWS stimulates c-jun binding to the tissue-type plasminogen activator cAMP responsive element consensus site modulating the expression of the specific gene downstream. These results confirm that RW metabolites affect the activity of different transcription factors playing an important preconditioning role in the modulation of the inflammatory pathway in endothelial cells. This is the first report on the effects of a complex food matrix, on the molecular mechanisms associated with inflammatory response in HUVEC cultured in condition that reproduces the physiological environment occurring in vivo.

SYNERGISTIC EFFECT OF PRESSURE, TEMPERATURE AND pH ON INACTIVATION OF BACILLUS SUBTILIS SPORES IN BUFFER AND MODEL FOOD SYSTEMS

ABSTRACT The combined pressure‐thermal‐pH influence on inactivation of Bacillus subtilis ATCC 6633 spores (1 × 108 cfu/mL initial count) in citrate‐phosphate buffer was studied over a range of pressure (690 and 827 MPa), process temperature (60, 65, 70 and 75C), pH (3, 5 and 7) and pressure‐holding time (up to 10 min) combinations. The influence of food matrix effect on spore inactivation was studied using tomato puree (pH 4.05) and minced crabmeat (pH 7.25) samples. All the experiments were conducted using a pilot‐scale high‐pressure food processor. Increase in process temperature, pressure and pressure‐holding time increased spore inactivation. Further, the substrate pH and the food substrate also had a significant influence on the spore inactivation. The highest inactivation (≥7 log10 units) was obtained when the spores suspended in pH 3 buffer were processed at 827 MPa–75C for 5 min. Adjusting the product formulation by adjusting its pH can be used as an effective tool in enhancing spore lethality during high‐pressure processing.PRACTICAL APPLICATIONSHigh‐pressure processing with or without the addition of heat has been used effectively as commercial food pasteurization method for a variety of value‐added food products. The current study will help further the development of high‐pressure processed high‐acid or acidified food products.

Effect of food matrix and heat treatment on the rheological properties of salmon-based baby food

Shelf stable baby foods from Alaskan salmon were developed from red and pink salmon with and without bones. The effect of salmon type, presence of bones and thermal treatment (121 °C for 55 min) on the dynamic (viscoelastic) and flow models were evaluated. Rheological behaviors of all samples were also tested over a temperature range of 25–55 °C. All samples had a higher viscoelastic behavior with consistently higher storage modulus ( G′) than loss modulus ( G″) over the entire frequency range used (0.5–100 rads/s at 25 °C). Thermal treatment had a significant effect ( p < 0.0001) on viscoelastic behavior of baby foods when the exponential model ( G′ or G″ = A( ω) b ) was used. A values were higher for the processed food for G′ and G″, and b values. The Casson model was found to be the best for the shear rate – shear stress for all types of tested samples. Retorted samples exhibited lower yield stress than their unretorted counterparts. Retorted samples were susceptible to temperature change more than unretorted samples as shown by energy of activation values ( E a ) when the effect of temperature (25–55 °C) was studied with an Arrhenius type model. Red salmon without bone had higher E a values among all samples and with pink salmon with bone recording a lowest among all of them.

Effect of Fat Content on the Digestibility and Bioaccessibility of Cocoa Polyphenol by an in Vitro Digestion Model

This work describes the applicability of an in vitro digestion model for the evaluation of the digestibility and bioaccessibility of cocoa polyphenols (procyanidins, phenolic acids, and flavones) and for the study of the food matrix effect in relation with the fat content. For this purpose, two cocoa samples, cocoa liquor ( approximately 50% fat content) and cocoa powder ( approximately 15% fat content), were used. The results showed an important increase of the concentration of procyanidin (monomers and dimers), probably due to the hydrolysis of procyanidins with a high degree of polymerization (pentamers to nonamers) submitted to the digestion procedure. In relation to flavones, the concentration of aglycone forms remained almost constant after the digestion steps; in contrast, the concentration of the glycoside forms an increase in the digestion mixtures mainly after the duodenal step, probably as a result of the partial digestion of the dietary fiber present in the cocoa. The higher fat content in the cocoa liquor seemed to have a protective effect, probably related with a better micellarization that favors the stability of polyphenols during digestion.

Rare, medium, or well done? The effect of heating and food matrix on food protein allergenicity

To review recent advances in the area of food allergen processing and the effect on protein allergenicity. Heating generally decreases protein allergenicity by destroying conformational epitopes. In peanut and shrimp, heat-induced Maillard reaction (glycation) may increase allergenicity. The majority of milk and egg-allergic children tolerate extensively heated (baked with wheat matrix) milk and egg. Introduction of extensively heated milk and egg proteins is associated with decreasing sizes of skin prick test wheals and increasing serum food-specific IgG4 levels. Heating and other methods of food processing have different effects on food allergens, even those contained in the same complex food. Structural homology does not reliably predict the effect of processing on allergenicity, and individual food allergens have to be tested. Interactions with other proteins, fat, and carbohydrates in the food matrix are complex and poorly understood. Introduction of extensively heated milk and egg proteins into the diet of allergic children may represent an alternative approach to oral tolerance induction. Better characterization of these aspects of food allergy is critical for elucidation of food protein interactions with the gut-associated lymphoid tissue, the ability to induce IgE sensitization, the potential to trigger hypersensitivity reactions, and different clinical phenotypes of food allergy with regard to severity and persistence.

Digestive Stability of Xanthophylls Exceeds That of Carotenes As Studied in a Dynamic in Vitro Gastrointestinal System1–3

Epidemiological studies have suggested that high consumption of tomato products is associated with a lower risk for chronic diseases. To exert their health effect, the phytochemicals of tomatoes have to be bioavailable and therefore it implies their stability through the digestion process. Here, we assessed the digestive stability of the red-pigmented lycopene and other carotenoids brought in nutritional quantity within different food matrixes, using the TNO gastrointestinal tract model (TIM). This multicompartmental dynamic system accurately reproduces the main parameters of gastric and small intestinal digestion in human. In vitro digestions of a standard meal containing red tomato (RT), yellow tomato (devoid of lycopene), or lycopene beadlets were performed. Zeaxanthin and lutein were stable throughout artificial digestions, whereas β-carotene and all-trans lycopene were degraded (∼30 and 20% loss at the end of digestion, respectively) in the jejunal and ileal compartments. The recovery of β-carotene in the digesta of the RT meal was significantly lower than that in the yellow one, showing a food matrix effect. In the same way, until 180 min of digestion, the recovery percentages of all-trans lycopene from RT were significantly lower than those issued from the supplement. Isomeric conformation also influenced the stability of carotenoids, 5-cis lycopene being the most stable isomer followed by all-trans and 9-cis. No trans-cis isomerization of lycopene occurred in the TIM. By using a relevant dynamic in vitro system, this study allowed us to gain further insight into the parameters influencing the digestive stability of carotenoids, and therefore their bioavailability, in humans.

Reaction Kinetics Analysis of Chemical Changes in Pressure-Assisted Thermal Processing

Pressure-assisted thermal processing (PATP) at T 100°C can be used when bacterial spores inactivation is necessary. In PATP, the adiabatic compression/decompression heat increases/decreases temperature almost instantaneously, and the simultaneous application of high pressure (~600–700 MPa) and temperature (~100–120°C) accelerates spore inactivation. PATP effects on chemical changes are analyzed using a reaction kinetics approach including activation volume (V a) and activation energy (E a) values. Reaction rates increase or decrease with pressure for negative or positive V a values, respectively, while rate temperature and pressure sensitivity depends on the magnitude of E a and V a values, respectively. The complex effects of food matrix, pH, dissolved oxygen, and presence of antioxidants show that optimization of vitamin, pigment and flavor retention while ensuring PATP microbial and enzyme inactivation will require substantially more chemical reaction kinetics research.

Optimization of the Measurement of Italian Monocultivar Extra Virgin Olive Oil Antioxidant Power Via the Briggs–Rauscher Reaction

In this paper, the overall antioxidant power of monocultivar extra virgin olive oil (EVOO) from Marche Region (Italy) was determined modifying, for the first time, the Briggs–Rauscher (BR) method to account for the water insolubility of the samples. The modification can pave the way to extend the BR antioxidant capacity assay to other real food systems that are usually heterogeneous mixtures and to easily take into account synergistic effects of antioxidants and food matrix that are essential to determine the antioxidant capacity; the pH of the method is the pH of gastric fluids, and this is noteworthy if we take into account that lipid peroxidation is amplified at this pH. The method is simple, rapid, and inexpensive. The interplay among antioxidant activity and total phenol content is rewarding and witness the feasibility of the method for the fast screening of antioxidant activity of EVOO samples.

Effect of Heating and Food Matrix on Egg White (EW) Protein Allergenicity

Effect of Heating and Food Matrix on Egg White (EW) Protein Allergenicity

Should digestion assays be used to estimate persistence of potential allergens in tests for safety of novel food proteins?

Food allergies affect an estimated 3 to 4% of adults and up to 8% of children in developed western countries. Results from in vitro simulated gastric digestion studies with purified proteins are routinely used to assess the allergenic potential of novel food proteins. The digestion of purified proteins in simulated gastric fluid typically progresses in an exponential fashion allowing persistence to be quantified using pseudo-first-order rate constants or half lives. However, the persistence of purified proteins in simulated gastric fluid is a poor predictor of the allergenic status of food proteins, potentially due to food matrix effects that can be significant in vivo. The evaluation of the persistence of novel proteins in whole, prepared food exposed to simulated gastric fluid may provide a more correlative result, but such assays should be thoroughly validated to demonstrate a predictive capacity before they are accepted to predict the allergenic potential of novel food proteins.

Power Ultrasound Treatment of Listeria monocytogenes in Apple Cider

Inactivation experiments with Listeria monocytogenes 10403S, an ultrasound-resistant strain, were conducted at sublethal (20, 30, and 40°C) and lethal (50, 55, and 60°C) temperatures in saline solution (pH 7.0), acidified saline solution (pH 3.4), and apple cider (pH 3.4) with and without application of ultrasound (20 kHz, 457 mW·ml−1). The survival of recoverable L. monocytogenes 10403S in apple cider was evaluated, and the effects of temperature, ultrasound, pH, and food matrix on inactivation were studied. Application of ultrasound increased the inactivation rate at both sublethal and lethal temperatures. Additional death of L. monocytogenes 10403S was due to low acidity at the lethal temperatures. The reduction in surviving L. monocytogenes 10403S followed first order kinetics at sublethal temperatures, but at lethal temperatures, a two-section linear model described the inactivation behavior. The bactericidal effect of thermosonication was additive in apple cider. The survival tests of L. monocytogenes 10403S in apple cider indicated the possibility of using a mild treatment condition in combination with ultrasound to achieve a 5-log reduction in number of listerial cells.

Absorption of isoflavones in humans: effects of food matrix and processing

If soy isoflavones are to be effective in preventing or treating a range of diseases, they must be bioavailable, and thus understanding factors which may alter their bioavailability needs to be elucidated. However, to date there is little information on whether the pharmacokinetic profile following ingestion of a defined dose is influenced by the food matrix in which the isoflavone is given or by the processing method used. Three different foods (cookies, chocolate bars and juice) were prepared, and their isoflavone contents were determined. We compared the urinary and serum concentrations of daidzein, genistein and equol following the consumption of three different foods, each of which contained 50 mg of isoflavones. After the technological processing of the different test foods, differences in aglycone levels were observed. The plasma levels of the isoflavone precursor daidzein were not altered by food matrix. Urinary daidzein recovery was similar for all three foods ingested with total urinary output of 33–34% of ingested dose. Peak genistein concentrations were attained in serum earlier following consumption of a liquid matrix rather than a solid matrix, although there was a lower total urinary recovery of genistein following ingestion of juice than that of the two other foods.

Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection

We describe a method for the determination of the two major urinary metabolites of vitamin K as the methyl esters of their aglycone structures, 2-methyl-3-(3'-3'-carboxymethylpropyl)-1,4-naphthoquinone (5C-aglycone) and 2-methyl-3-(5'-carboxy-3'-methyl-2'-pentenyl)-1,4-naphthoquinone (7C-aglycone), by HPLC with electrochemical detection (ECD) in the redox mode. Urinary salts were removed by reversed-phase (C18) solid-phase extraction (SPE), and the predominantly conjugated vitamin K metabolites were hydrolyzed with methanolic HCl. The resulting carboxylic acid aglycones were quantitatively methylated with diazomethane and fractionated by normal-phase (silica) SPE. Final analysis was by reversed-phase (C18) HPLC with a methanol-aqueous mobile phase. Metabolites were detected by amperometric, oxidative ECD of their quinol forms, which were generated by postcolumn coulometric reduction at an upstream electrode. The assay gave excellent linearity (typically, r2 > or = 0.999) and high sensitivity with an on-column detection limit of < 3.5 fmol (< 1 pg). The interassay precision was typically 10%. Metabolite recovery was compared with that of an internal standard [2-methyl-3-(7'-carboxy-heptyl)-1,4-naphthoquinone] added to urine samples just before analysis. Using this methodology, we confirmed that the 5C- and 7C-aglycones were major catabolites of both phylloquinone (vitamin K1) and menaquinones (vitamin K2) in humans. We propose that the measurement of urinary vitamin K metabolite excretion is a candidate noninvasive marker of total vitamin K status.

Effect of Food Matrix and Cell Growth on PCR-Based Detection of Escherichia coli O157:H7 in Ground Beef

The purpose of this work was (i) to investigate the feasibility of a previously reported upstream processing method for PCR template preparation to facilitate the detection of Escherichia coli O157:H7 from ground beef and (ii) to assess the impact of cell growth (no growth in the matrix versus growth in the matrix) on molecular detection limits. Two food matrices (autoclaved and raw ground beef) were evaluated in all studies. For no-growth experiments, 10-g meat samples were inoculated with 102 to 107 CFU/g E. coli O157:H7 and then homogenized. The homogenates were processed to remove large particulates and inhibitors using a two-phase upstream processing method consisting of two sequential centrifugation steps, the second of which used titanous hydroxide to facilitate bacterial immobilization. After upstream processing, sample concentrates were extracted for DNA isolation and amplified by PCR. For growth experiments, 10-g meat samples were inoculated at 1 CFU of E. coli O157:H7 per gram, allowed to grow to 102 to 107 CFU/g, and then processed for PCR assay. Cell recoveries after upstream processing ranged from 15.9 to 77.6% and were not facilitated by the use of titanous hydroxide, as compared with a saline control (P > 0.05). Bacterial cell recovery and PCR detection limits were similar when comparing autoclaved ground beef and raw ground beef, but cell recoveries were highly variable for raw ground beef samples in which E. coli O157:H7 cells were allowed to grow before processing for detection. Overall, PCR detection limits approximated 103 CFU/g of ground beef for all treatments. These results indicate that use of model food systems may not always provide an accurate replication of real-world conditions when evaluating PCR detection limits.

Comparison of the thermal inactivation of Bacillus subtilis spores in foods using the modified Weibull and Bigelow equations

The association of a modified Weibull model and Bigelow model was applied to the thermal inactivation of Bacillus subtilis spores heated in phosphate buffer, milk, kayu (a Japanese style rice porridge) and soy sauce as well. The inactivation kinetics presented a light downward concave profile, the acidic pH increased the efficiency of the heat treatment but on the opposite, lesser the water activity, weaker was the efficiency. The heat treatment kinetics observed in milk, soy sauce and kayu were greatly different from each other, while no large difference between sterilized whole milk, UHT whole milk, sterilized skim milk and UHT skim milk, were observed. The model established in buffer system allowed heat treatment in milk products to be simulated although it could not be employed to describe the inactivation of B. subtilis spores in soy sauce and kayu. For these two latter products, the food itself had to be introduced in the model as a parameter. Finally, this approach combining primary model (to simulate inactivation kinetics) and secondary model (to introduce temperature, pH, aw and food matrix effect) seemed available for food application, nevertheless validations of results such as challenge-tests, must be performed before it is put to routine use.

Food matrix effects on bioactivity of broccoli-derived sulforaphane in liver and colon of F344 rats.

Sulforaphane (SF) is considered to be the major anticarcinogenic component in broccoli. The effects of feeding rats purified SF (5 mmol/kg of diet), broccoli containing SF formed in situ during laboratory hydrolysis (broccoli-HP; 20% freeze-dried broccoli diet, 0.16 mmol of SF/kg of diet), and broccoli containing intact glucosinolates (broccoli-GS; 20% freeze-dried broccoli diet, 2.2 mmol of glucoraphanin/kg of diet) were compared. Rats (male F344 rats, five per group) were fed control (modified AIN-76 B-40), SF, broccoli-HP, or broccoli-GS for 5 days. In rats fed broccoli-GS, quinone reductase activities (QR) in the colon and liver were greater (4.5- and 1.4-fold over control, respectively) than in rats fed broccoli-HP (3.2- and 1.1-fold over control, respectively). Broccoli-GS and SF diets increased QR to the same extent, even though the broccoli-GS diet contained far less SF (as the unhydrolyzed glucosinolate, glucoraphanin) than the purified SF diet. In a second experiment, rats were fed one of six diets for 5 days: (1) control; (2) 20% broccoli-GS; (3) diet 2 + low SF (0.16 mmol/kg of diet); (4) diet 2 + high SF (5 mmol/kg of diet); (5) low SF (0.32 mmol/kg of diet); or (6) high SF (5.16 mmol/kg of diet). In both liver and colon, QR was increased most by high SF plus broccoli-GS; individually, high SF and broccoli-GS had similar effects, and adding the low-dose SF to broccoli-GS had either no effect or a negative effect. In both experiments, urinary SF-mercapturic acid correlated with QR activity, not with dietary intake. It was concluded that all diets were substantially more effective in the colon than in the liver and that broccoli-GS was more potent than SF or broccoli-HP.

Aufreinigung von Fumonisinen und ihren Hydrolysaten über ein neuartiges Festphasenextraktions-Material

Tests with various clean-up materials after optimisation of different parameters showed that the use of Oasis® material resulted in matrixless chromatograms in HPLC-FLD. The selectivity and detection limit of the method was improved by using LC-MS/MS as the detection system. Mean recovery was 100%, and no negative food matrix effects could be observed.

Hypothesis: the protein body effect and other aspects of food matrix effects.

With regard to the allergenicity of edible seeds and nuts, certain proteins may not be immediately accessible to digestion in the stomach and the upper small intestine because of the nature of the organization of such proteins into protein body organelles. Protein body hydration status, interactions between proteins, phytochemicals, protease inhibitors, and other matrix effects may contribute to the ability of a protein or package of proteins to reach the sites of active immune sampling in the gastrointestinal mucosa and thus be an influence on the potential allergenicity of a protein.

PCR assay for detection of the E. Coli O157:H7 eae-gene and effect of the sample preparation method on PCR detection of heat-killed E. coli O157:H7 in ground beef

A PCR assay targeting the 3′ end of the eae-gene of E. coli O157:H7 has been developed. It was shown to be specific for the E. coli O157:H7 eae-gene. Sensitivity of the PCR assay was 1 pg DNA or 10 3 cfu per PCR reaction. Subsequently, a study was conducted to examine the effect of the food matrix and the sample preparation method on PCR detection of non-viable cells using heat-killed E. coli O157:H7 in ground beef as a model system. Inoculated ground beef samples were subjected to either selective enrichment or immediately prepared for PCR analysis. Four sample preparation methods were applied: centrifugation, buoyant density centrifugation (BDC), immunomagnetic separation (IMS), and chelex extraction. Production of false-positive results due to amplification of the DNA of dead cells occurred if the number of heat-killed cells exceeded 10 8 cfu/g. For inocula <10 8 cfu/g, PCR results for heat- killed E. coli O157:H7 cells depended upon the sample preparation method. It was shown that the inclusion of two washings steps of the bacterial pellet before DNA extraction was the critical factor for elimination of false-positive results due to heat-killed cells in the centrifugation and BDC procedure. IMS did not produce false-positive results due to heat-killed cells (two washing steps were included in the IMS procedure). With the chelex-extraction method, false-positive results due to heat-killed cells were obtained. An effect of the ground beef food matrix on the presence of amplifiable DNA was noted.