Enterococcus faecium as a Salmonella surrogate in the thermal processing of wheat flour: Influence of water activity at high temperatures

This study investigated the influence of temperature-dependent water activity (a_w) on thermal resistances of Enterococcus faecium NRRL B-2354 (E. faecium) and Salmonella Enteritidis PT 30 (S. Enteritidis) in wheat flour. The a_w for wheat flour samples at 20, 40, and 60 °C was determined by a vapor sorption analyzer and at 75, 80 and 85 °C using custom-built thermal cells with high temperature humidity sensors. Full-factorial isothermal inactivation studies of both strains in sealed aluminum-test-cells included three temperatures (75, 80, and 85 °C) and three a_w,25°C levels (0.30, 0.45 and 0.60 within ±0.02 range, prior to the thermal treatments). Isotherm results of wheat flour demonstrate a significant increase (P < 0.05) of a_w as temperature rises (e.g. a_w,25°C = 0.45 ± 0.02 became a_w,80°C = 0.71 ± 0.02 in a closed system). Inactivation kinetics of both microorganisms fitted a log-linear model, the yielded D-values varied from 2.7 ± 0.2 min (D_85°C of S. Enteritidis at a_w,25°C 0.60 ± 0.02) to 65.8 ± 2.5 min (D_75°C of E. faecium at a_w,25°C 0.30 ± 0.02). The z_T of E. faecium and S. Enteritidis decreased from 16.4 and 16.9 °C, respectively, to 10.2 °C with increased moisture content (dry basis) from 10 to 14%. Under all tested conditions, E. faecium exhibited equal or higher (1.0-3.1 times) D- and z_T-values than those of Salmonella. Overall, E. faecium should be a conservative surrogate for Salmonella in thermal processing of wheat flour for control of Salmonella over a moisture content of 10-14% and treatment temperatures between 75 and 85 °C.

Characterization of cookies made from wheat flour blended with buckwheat flour and effect on antioxidant properties

Buckwheat flour was incorporated into wheat flour at different levels (0, 20, 40, 60, 80, and 100 %) and the physicochemical, functional and antioxidant properties of the blended flour were studied. This study also investigated the effect of buckwheat on the retention of antioxidant properties of cookies during baking. The results showed significant variation in physicochemical and functional properties of the blended flour. The addition of buckwheat flour into wheat flour also increased the antioxidant properties of blended flour proportionally, but metal chelating properties decreased. The incorporation of buckwheat in wheat flour helped in better retention of antioxidant potential of cookies during baking process as buckwheat cookies (100 % buckwheat) showed greater percentage increase in antioxidant properties than control (100 % wheat). Quality characteristics of cookies such as hardness and spread ratio decreased, while as non-enzymatic browning (NEB) increased significantly with increase in the proportion of buckwheat flour in wheat flour. The Overall acceptability of cookies by sensory analysis was highest at 40 % level of blending. This study concluded that addition of buckwheat in wheat flour, may not only improve the physico-chemical and functional properties of the blended flour but may also enhance the nutraceutical potential of the product prepared from it.

Effects of dry heat treatment temperature on the structure of wheat flour and starch in vitro digestibility of bread

The effects of the dry heat treatment (DHT) temperature (20, 50, 100, 150, 200 °C) on the structure of wheat flour and on the texture and in vitro starch digestibility of breads were investigated. X-ray diffraction and FTIR showed that increasing temperatures produced reduction of the hydrated starch structures, increased crystallinity and molecular order of starch chains, and had important effects on the gluten secondary structure. High treatment temperatures produced significant reductions in rapidly digestible starch (RDS) (53.21% at 20 °C, 22.24% at 200 °C), and the slowly digestible starch fraction tended to increase (26.12% at 20 °C, 31.48% at 200 °C). On the other hand, bread hardness showed a significant increase from 11.25 N at 20 °C to 49.53 N at 200 °C, the latter value being similar to that reported for bread crusts. Principal component analysis results showed that the flour and bread characteristics were drastically changed by the DHT, with 100 °C representing a critical temperature. Below 100 °C, breads showed textural characteristics close to that of the control bread, with reduced RDS fractions, while at temperatures above 100 °C, hardness was boosted.

Gamma irradiation effects on ochratoxin A: Degradation, cytotoxicity and application in food

Ochratoxin A (OTA) is one of the main mycotoxins that can be found in food. The use of gamma radiation is a technique for preserving food that may exert some effects on mycotoxins. OTA was irradiated in its dry form, in aqueous and in methanolic solutions, and in wheat flour, grape juice and wine. Additionally, the toxicity of OTA irradiated in water was tested. In aqueous solutions, more than 90% of the OTA was degraded by γ-radiation doses ≥2.5kGy, and a 2-fold reduction in OTA cytotoxicity was observed. In food matrices, the elimination of OTA by γ-radiation was found more difficult, as radiation doses of 30kGy eliminate at most 24% of the OTA. Higher moisture content of food matrices did not substantially increase OTA elimination. It is concluded that OTA is very sensitive to irradiation in water solutions but resistant in its dry form and in food matrices.

Production of low chlorogenic and caffeic acid containing sunflower meal protein isolate and its use in functional wheat bread making

Sunflower meal protein isolate (SMPI) is a promising food additive in different matrices. However, the uses of SMPI are limited because of the presence of antinutritional compounds like polyphenolic substances. Chlorogenic and caffeic acids are the dominants polyphenolics in the SMPI. These substances cause significant changes of the colour of the meal, proteins and food matrices during their extraction and use as food additives. Moreover, these substances lower the nutritional value of the end product due to their interaction with some amino acids such as lysine and methionine. Thus, the removal of these substances is important to enable the use of the SMPI and meal in general in a greater extent in food applications and replacing more expensive protein sources such as soy proteins. The aim of this work was to study the production of functional bread by supplementing wheat flour with sunflower meal protein isolate (SMPI). SMPI with low content of chlorogenic and caffeic acid was usefully produced following alkaline extraction and purification with succinic acid. Purified SMPI showed well balanced amino acid profile and was characterized by high water and fat absorption capacities. It was incorporated to dough formula at 8-12 % of the total wheat flour. The results showed that production of bread supplemented with SMPI was technologically feasible. The supplemented bread had high mass volume and nutritional quality compared to the control bread. The optimal SMPI to incorporate into dough formula without significant alteration of the final bread colour was established at 10 %. This study will be helpful to find economic ways to enhance the nutritional quality of wheat bread and to improve the profitability of sunflower meal residue.

Jet milling effect on wheat flour characteristics and starch hydrolysis

The interest for producing wheat flour with health promoting effect and improved functionality has led to investigate new milling techniques that can provide finer flours. In this study, jet milling treatment was used to understand the effect of ultrafine size reduction onto microstructure and physicochemical properties of wheat flour. Three different conditions of jet milling, regarding air pressure (4 or 8 bars) feed rate and recirculation, were applied to obtain wheat flours with different particle size (control, F1, F2 and F3 with d50 127.45, 62.30, 22.94 and 11.4 μm, respectively). Large aggregates were gradually reduced in size, depending on the intensity of the process, and starch granules were separated from the protein matrix. Damaged starch increased while moisture content decreased because of milling intensity. Notable changes were observed in starch hydrolysis kinetics, which shifted to higher values with milling. Viscosity of all micronized samples was reduced and gelatinization temperatures (To, Tp, Tc) for F2 and F3 flours increased. Controlling jet milling conditions allow obtaining flours with different functionality, with greater changes at higher treatment severity that induces large particle reduction.

Predicting micronutrients of wheat using hyperspectral imaging

Micronutrients are the key factors to evaluate the nutritional quality of wheat. However, measuring micronutrients is time-consuming and expensive. In this study, the potential of hyperspectral imaging for predicting wheat micronutrient content was investigated. The spectral reflectance of wheat kernels and flour was acquired in the visible and near-infrared range (VIS-NIR, 375-1050 nm). Afterwards, wheat micronutrient contents were measured and their associations with the spectra were modeled. Results showed that the models based on the spectral reflectance of wheat kernel achieved good predictions for Ca, Mg, Mo and Zn (r²>0.70). The models based on the spectra reflectance of wheat flour showed good predictive capabilities for Mg, Mo and Zn (r²>0.60). The prediction accuracy was higher for wheat kernels than for the flour. This study showed the feasibility of hyperspectral imaging as a non-invasive, non-destructive tool to predict micronutrients of wheat.

Quantification of sugars in wheat flours with an HPAEC-PAD method

An HPAEC-PAD method has been developed and validated for the simultaneous determination and quantification of six sugars (glucose, isomaltose, maltose, maltotriose, maltotetraose and maltopentaose) in wheat flours, by extraction with water and precipitation of proteins with Carrez II. Analyses were carried out on a Hamilton RCX-30 column with a gradient elution of NaOH 50mM (A) and NaOH 50mM+NaAcO 500 mM (B). Total run time was 38 min. Detector conditions were as follows: E1, +100 mV; E2, +550 mV; E3, -100 mV. The method was validated, with LODs ranging between 0.03-0.21 mg L(-1) and LOQs between 0.10-0.71 mg L(-1), R(2) between 0.9941 and 0.9983; recoveries were from 74.16% to 110.86% and RSDs for intraday repeatability, interday repeatability and reproducibility between 0.35-8.34%, 2.34-6.64% and 1.90-5.68%, respectively. The method was successfully applied to quantification of these sugars in wheat flours.

MIP-MEPS based sensing strategy for the selective assay of dimethoate. Application to wheat flour samples

The aim of this work was to demonstrate the potentialities of the use of a molecularly imprinted (MIP) sensor coupled to a microextraction by packed sorbent (MEPS) strategy for the selective and sensitive detection of dimethoate in real samples. A dimethoate-polypyrrole MIP film was realised by cyclic voltammetry (CV) on the surface of a glassy carbon electrode (GCE). Being dimethoate electro-inactive, K₃[Fe(CN)₆] was used as probe for the indirect quantification of the analyte via the decrease of redox peaks observed upon binding of the target analyte. Detection of dimethoate at low nanomolar range was achieved with linearity in the 0.1-1nM range. Relative standard deviation calculated for different electrodes at 0.5nM of dimethoate was < 3% and selectivity was very satisfactory being the response for omethoate only 23% of dimethoate. A MEPS strategy for the extraction of dimethoate from a challenging matrix as wheat flour was then used in conjunction with the MIP electrochemical sensor. The procedure applied to flour samples spiked with dimethoate at 0.5 MRL, MRL, and 1.5 MRL gave very favourable comparison with a validated UHPLC-MS/MS method with deviations in the -21% /+17% range, demonstrating the feasibility of the approach as screening assay. This work clearly shows that the sequential use of a microextraction based procedure and electrochemical sensing system is low cost, easy to realise and use and can open new perspectives for the development of selective sensing system to be used in field or decentralised lab testing for the selective screening of target analytes.

Human health risk assessment of heavy metals in the irrigated area of Jinghui, Shaanxi, China, in terms of wheat flour consumption

Contamination of heavy metals (HMs) in agricultural soil has become a serious environmental problem because it poses a serious threat to human health by entering into food chains. Wheat is a staple food of the majority of the world's population; therefore, understanding the relationship between HM concentration in soils and its accumulation in wheat grain is imperative. This study assessed the concentrations of HMs (i.e., Hg, As, Cd, Cr, Pb, Cu, Zn, and Ni) in agricultural soils (a loess soil, eum-orthic anthrosol) and wheat flour in the historical irrigated area of Jinghui, Northwest China. The potential human health risks of HMs among local residents were also determined by evaluating the consumption of wheat flour. Results showed that the mean soil concentrations of HMs exceeded the corresponding natural background values of agricultural surface soil in Shaanxi: 0.07 mg kg(-1) for Hg, 15.4 mg kg(-1) for As, 0.25 mg kg(-1) for Cd, 75.5 mg kg(-1) for Cr, 27.2 mg kg(-1) for Pb, 28.1 mg kg(-1) for Cu, 81.1 mg kg(-1) for Zn, and 36.6 mg kg(-1) for Ni, respectively. However, all of the mean concentrations of HMs in soil were within the safety limits set by the Chinese regulation (HJ332-2006). The total HM concentrations in wheat flour were 0.0017 mg kg(-1) for Hg, 0.028 mg kg(-1) for As, 0.020 mg kg(-1) for Cd, 0.109 mg kg(-1) for Cr, 0.128 mg kg(-1) for Pb, 2.66 mg kg(-1) for Cu, 24.20 mg kg(-1) for Zn, and 0.20 mg kg(-1) for Ni, and they were significantly lower than the tolerance limits of Chinese standards. However, 15% of the wheat flour samples exceeded the Chinese standard (GB2762-2012) for Pb. This study highlighted the human health risks in the relationship of wheat flour consumption for both adults and children with HMs accumulated area. HMs did not cause noncarcinogenic risks in the area (HI < 1) except for children in Jingyang county; Cd generated the greatest carcinogenic risk, which poses a potential health risk to consumers. The results obtained in this study showed that the government and other institutions should implement measures to prevent and control HM contamination in agricultural soil and crops to mitigate the associated health risks.

Effect of wheat species (Triticum aestivum vs T. spelta), farming system (organic vs conventional) and flour type (wholegrain vs white) on composition of wheat flour - Results of a retail survey in the UK and Germany - 2. Antioxidant activity, and phenolic and mineral content

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Whole-grain flours had 2–5 times higher antioxidant and mineral levels than white flour.

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Organic flour had higher antioxidant and mineral levels than conventional flour.

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Organic flour had a higher Al and Ni content than conventional flour.

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Spelt wheat had higher antioxidant and mineral levels than common wheat flour.

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Spelt wheat had a 28% higher Cd content than conventional flour.

There is strong evidence for health benefits from whole-grain wheat consumption and these have been linked to their higher fibre, antioxidant/(poly)phenolic and mineral contents. However, there is still scientific controversy about the relative effect of wheat species (Triticum aestivum vs T. spelta) and production methods (conventional vs organic) on the nutritional composition of wheat. The retail survey reported here showed that, the use of spelt varieties and organic production results in significantly higher (between 10 and 64%) levels of phenolics and some minerals in wheat flour. However, the relative effect of removing the outer bran and germ during milling was substantially larger; levels of antioxidant activity, and many phenolic compounds and mineral nutrients were 2–5 times higher in whole-grain than white flour. Organic flour contained higher concentrations of the undesirable metals Al and Ni (12% and 81% respectively), and spelt flour had 28% higher concentrations of the toxic metal Cd.

Wheat is an emerging exposure route for arsenic in Bihar, India

In arsenic (As) endemic areas of south-east Asia, where a subsistence rice-based diet is prevalent, As exposure from food is mainly focused on rice intake. However, consumption of wheat is substantial and increasing. We present a probabilistic assessment of increased cancer risk from wheat-based food intake in a study population of rural Bihar, India where As exposure is endemic. Total As in wheat grains (43.64 ± 48.19 µg/kg, n = 72) collected from 77 households across 19 villages was found to be lower than reported As in wheat grains from other south-east Asian countries but higher than a previous study from Bihar. This is the first study where As concentration in wheat flour was used for risk estimation, bearing in mind that it was the flour obtained after indigenous household processing of the grains that was used for making the home-made bread (chapati) which contributed 95% of wheat intake for the studied population. Interestingly, while 78% of the surveyed participants (n = 154) consumed rice every day, chapati was consumed every day by 99.5% of the participants. In contrast to previous studies, where As concentration in wheat grains was found to be lower than the flour due to the removal of the bran on grinding, we did not find any appreciable lowering of arsenic in the wheat flour (49.80 ± 74.08 µg/kg, n = 58), most likely due to external contamination during processing and grinding. Estimated gender adjusted excess lifetime cancer risk of 1.23 × 10^-4 for the studied rural population of Bihar indicated risk higher than the 10^-4-10^-6 range, typically used by the USEPA as a threshold to guide regulatory values. Hence, our findings suggest As exposure from wheat-based food intake to be of concern not only in As endemic areas of rural Bihar but also in non-endemic areas with similar wheat-based diet due to public distribution of the wheat across India.

Evaluation of dough rheological properties and bread texture of pearl millet-wheat flour mix

This study was undertaken with the objective of formulating composite bread using pearl millet (Pennisetum glaucum) and wheat (Triticum aestivum) flours . Rheological and bread making properties of composite flours were evaluated. Mixolab results revealed torque increased and dough stability time decreased upon incorporation of pearl millet flour in wheat flour. The incorporation of millet flour at optimum level (5 %) led to an increase of the dough strength (W) and the elasticity-to-extensibility ratio (P/L) by 31 % and 65 % respectively. The bread texture and volume were also improved. These findings indicated the potentiality of using millet flour in bread making.

Towards reducing the immunogenic potential of wheat flour: omega gliadins encoded by the D genome of hexaploid wheat may also harbor epitopes for the serious food allergy WDEIA

BACKGROUND

Omega-5 gliadins are a group of highly repetitive gluten proteins in wheat flour encoded on the 1B chromosome of hexaploid wheat. These proteins are the major sensitizing allergens in a severe form of food allergy called wheat-dependent exercise-induced anaphylaxis (WDEIA). The elimination of omega-5 gliadins from wheat flour through biotechnology or breeding approaches could reduce the immunogenic potential and adverse health effects of the flour.

RESULTS

A mutant line missing low-molecular weight glutenin subunits encoded at the Glu-B3 locus was selected previously from a doubled haploid population generated from two Korean wheat cultivars. Analysis of flour from the mutant line by 2-dimensional gel electrophoresis coupled with tandem mass spectrometry revealed that the omega-5 gliadins and several gamma gliadins encoded by the closely linked Gli-B1 locus were also missing as a result of a deletion of at least 5.8 Mb of chromosome 1B. Two-dimensional immunoblot analysis of flour proteins using sera from WDEIA patients showed reduced IgE reactivity in the mutant relative to the parental lines due to the absence of the major omega-5 gliadins. However, two minor proteins showed strong reactivity to patient sera in both the parental and the mutant lines and also reacted with a monoclonal antibody against omega-5 gliadin. Analysis of the two minor reactive proteins by mass spectrometry revealed that both proteins correspond to omega-5 gliadin genes encoded on chromosome 1D that were thought previously to be pseudogenes.

CONCLUSIONS

While breeding approaches can be used to reduce the levels of the highly immunogenic omega-5 gliadins in wheat flour, these approaches are complicated by the genetic linkage of different classes of gluten protein genes and the finding that omega-5 gliadins may be encoded on more than one chromosome. The work illustrates the importance of detailed knowledge about the genomic regions harboring the major gluten protein genes in individual wheat cultivars for future efforts aimed at reducing the immunogenic potential of wheat flour.

How fructophilic lactic acid bacteria may reduce the FODMAPs content in wheat-derived baked goods: a proof of concept

BACKGROUND

FODMAPs (Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) intake is associated with the onset of irritable bowel syndrome symptoms. FODMAPs in wheat-derived baked goods may be reduced via bioprocessing by endogenous enzymes and/or microbial fermentation. Because of the inherent enzyme activities, bread made by baker's yeast and sourdough may result in decreased levels of FODMAPs, whose values are, however, not enough low for people sensitive to FODMAPs.

RESULTS

Our study investigated the complementary capability of targeted commercial enzymes and metabolically strictly fructophilic lactic acid bacteria (FLAB) to hydrolyze fructans and deplete fructose during wheat dough fermentation. FLAB strains displayed higher fructose consumption rate compared to conventional sourdough lactic acid bacteria. Fructose metabolism by FLAB was faster than glucose. The catabolism of mannitol with the goal of its reuse by FLAB was also investigated. Under sourdough conditions, higher fructans breakdown occurred in FLAB inoculated doughs compared to conventional sourdough bacteria. Preliminary trials allowed selecting Apilactobacillus kunkeei B23I and Fructobacillus fructosus MBIII5 as starter candidates, which were successfully applied in synergy with commercial invertase for low FODMAPs baking.

CONCLUSIONS

Results of this study clearly demonstrated the potential of selected strictly FLAB to strongly reduce FODMAPs in wheat dough, especially under liquid-dough and high oxygenation conditions.

Technological quality of dough and breads from commercial algarroba-wheat flour blends

Algarroba flour is used to supplement lysine-limiting systems such as wheat flour due to its amino acidic composition. The effects of adding up to 30% of this flour to wheat flour (W-A30) on dough characteristics and breadmaking performance were studied. Dough rheology was tested by farinograph, oscillatory rheometry and texture profile analyses. Molecular mobility was evaluated by nuclear magnetic resonance, and thermal properties were analyzed by differential scanning calorimetry and viscoamylograph studies. Besides, different bread quality parameters were evaluated. Incorporation of algarroba flour resulted into increase in water absorption, development time and degree of softening, and decrease in stability of wheat flour, leading to softer, less adhesive and elastic dough, although at intermediate replacement levels cohesiveness improved. At the molecular level, a reduction of water activity and limited proton motion were observed in W-A30 samples, suggesting that protons were highly bound to the dough matrix. Dough samples with algarroba flour showed lower G' and G″ values than the control, although with the formation of a more elastic structure for W-A30. In addition, algarroba flour produced a protective effect on starch granule disruption and interfered with amylose-amylose association during cooling. The specific volume of breads decreased with the increase in algarroba level, W-A30 reaching the highest decrease (15%). Bread crumbs with algarroba flour exhibited higher values of hardness and resilience. The use of algarroba flour resulted in lower quality when compared to the control. However, algarroba flour at 20% level can be added to wheat flour to obtain bakery products of similar technological quality and with improved nutritional components.

Use of response surface methodology to investigate the effects of brown and golden flaxseed on wheat flour dough microstructure and rheological properties

The aim of this study was to assess the effects of brown flaxseed and golden flaxseed on the water absorption and the rheological parameters of wheat flour. The rheological properties were evaluated by the Mixolab. The optimum parameters were identified for high quality flaxseed-wheat composite flour bread. Each predictor variable was tested at five levels. The microstructure of dough was assessed by epifluorescence light microscopy. The substitution of 4.81/100 g for brown flaxseed and 5.07/100 g for golden flaxseed was found optimal. At the optimum level of brown and golden flaxseed, the water absorption of 55.07/100 g, dough development time of 1.28 min and dough stability of 10.04 min was observed. In terms of protein quality the optimum values were 0.41 N m for C2 and 0.69 for C1-2, and in terms of starch characteristics they were 1.56 N m for C3, 1.14 for C3-2, 1.33 N m for C4, 0.20 for C3-4, 1.97 N m for C5 and 0.60 for C5-4.

Lentil sprouts: a nutraceutical alternative for the elaboration of bread

The pro-health action of germinated lentils could be useful to be added with wheat flour in the production of box bread. In this work, we spectroscopically evaluate the germinated and non-germinated lentils, and use them at the concentrations of 5 and 10% for the production of box bread. The chemical and physical tests of the bread and its determination of phenolic acids and flavonoids (by HPLC) were also performed. As well as the evaluation of the quality of flour and dough used to produce the bread and the acceptance of the germinated lentil bread with a population of 20 people with diabetes or with diabetic relatives It is shown that: (1) The amplitude of photoacoustic signal obtained by photoacoustic spectroscopy is modified as a function of the percentage of germinated lentil (GL) flour (0, 5 or 10%) add to the bread; being higher the photoacoustic amplitude to higher concentration of GL in the absorption band of 300-425 nm, which is related to higher content of phenols and flavonoids. (2) The contents of phenolic acids (Sinapinic, β- resorcylic, Chlorogenic and Ferulic) and flavonoids (Quercetin and Isorhamnetin) tended to increase in the germinated lentil bread with 10% concentration of germinated lentil flour with respect to the control bread (0% GL). (3) The addition of germinated lentils flour to 5 and 10% into wheat flour to produce bread with higher hardness and less cohesiveness than bread based on wheat flour only. The Falling number indicate that there is no significant difference between the control sample and the 5% GL flour, while in the 10% GL flour there was a reduction of 21 s, with respect to the control. The effect of the germinated lentil flour percentage on the pasting properties of the flours was significant between the control and 10% GL flour. In general, the quality of the dough and flour are modified due to the addition of germinates lentils, and this affectation increases with the increase in the concentration of GL. (4) The bread added with germinated lentil has sensory acceptance with a group of people with diabetes and/or diabetic relatives in their attributes in general. The obtained results thus support the production of wheat bread with mixed germinated lentils flour, as a nutraceutical option for human consumption.

Determination of adulteration in wheat flour using multi-grained cascade forest-related models coupled with the fusion information of hyperspectral imaging

Wheat flour (WF) is a common ingredient in staple foods. However, the presence of intentional or unintentional adulterants makes it difficult to guarantee WF quality. Multi-grained cascade forest (gcForest) model, a non-neural network deep learning structure, fused with image-spectra features from hyperspectral imaging (HSI) was employed for detecting adulterant type (peanut, walnut, or benzoyl peroxide) and the corresponding concentration (0.03%, 0.05%, 0.1%, 0.5%, 1%, and 2%). Based on the spectra of full wavelength and effective wavelength (EW) from hyperspectral images of WF samples, the gcForest-related models exhibited high performance (lowest ACC_P = 92.45%) and stability (lowest area under the curve = 0.9986). Furthermore, the fusion of the EW and the image features extracted by the symmetric all convolutional neural network (SACNN) was used to establish the gcForest-related models. The maximum accuracy improvement of the fusion feature model relative to the single spectral model and the image model was 2.45% and 44.37%, respectively. The results indicate that the gcForest-related model, combined with the image-spectra fusion feature of HSI, provides an effective tool for detection in food and agriculture.

Effect of Vacuum Steam Treatment of Hard Red Spring Wheat on Flour Quality and Reduction of Escherichia coli O121 and Salmonella Enteritidis PT 30

ABSTRACT

Recent outbreaks traced to contaminated flour have created a need in the milling industry for a process that reduces pathogens in wheat while maintaining its functional properties. Vacuum steam treatment is a promising technology for treatment of low-moisture foods. Traditional thermal treatment methods can compromise wheat functionality due to high temperatures; thus, maintaining the functional quality of the wheat protein was critical for this research. The objective of this study was to evaluate the effect of vacuum steam treatment of hard red spring (HRS) wheat kernels on final flour quality and the overall efficacy of vacuum stream treatment for reducing pathogens on HRS wheat kernels. HRS wheat samples were treated with steam under vacuum at 65, 70, 75, and 85°C for 4 and 8 min. Significant changes in dough and baked product functionality were observed for treatments at ≥70°C. Treatment time had no significant effect on the qualities evaluated. After determining that vacuum steam treatment at 65°C best preserved product quality, HRS wheat was inoculated with Escherichia coli O121 and Salmonella Enteritidis PT 30 and processed at 65°C for 0, 2, 4, 6, or 8 min. The treatments achieved a maximum average reduction of 3.57 ± 0.33 log CFU/g for E. coli O121 and 3.21 ± 0.27 log CFU/g for Salmonella. Vacuum steam treatment could be an effective pathogen inactivation method for the flour milling industry.

HIGHLIGHTS

Relationship of Mixolab characteristics with protein, pasting, dynamic and empirical rheological characteristics of flours from Indian wheat varieties with diverse grain hardness

Mixolab properties of different Indian extraordinarily soft (Ex-SW), hard (HW) and medium hard (MHW) wheat varieties were evaluated and related to damaged starch content, particle size distribution, pasting, Farinographic and Mixographic properties. Water absorption (WA) of HW varieties was higher as compared to other varieties. Higher damaged starch led to more WA in HW varieties while lower in Ex-SW varieties. Unextratable polymeric protein, damaged starch and arabinoxylans were related to dough consistency. Mixolab measurement C3 (peak viscosity) and C5 (starch retrogradation) decreased with increase in grain hardness index, damaged starch content, and sodium solvent retention capacity. Dough stability (DS) and dough development time (DDT) measured by Mixolab and farinograph were significantly correlated. Mixolab parameters (C3, C4 and C5) related positively to DDT and DS while negatively to WA. HW varieties showed higher shear thinning as compared to MHW and Ex-SW varieties. C4 (hot paste stability) was lower for HW but higher for Ex-SW varieties. SuSRC was negatively related to C4 indicating that HW flours had lower starch retrogradation due to higher arabinoxylans. C3, C4 and C5 related positively to small size particles while negatively to large size particles. Slope beta (β) measured by mixolab indicated that the speed of starch gelatinization was lower for Ex-SW varieties than MHW and HW varieties.

Quality characteristics of bread produced from wheat, rice and maize flours

Rice (Oryza sativa) flour and maize (Zea mays) meal substitution in wheat (Triticum aestivum) flour, from 0 to 100% each, for the production of bread was investigated. The proximate analysis, pasting properties, bread making qualities of raw materials and sensory evaluation of the bread samples were determined. The pasting temperature increased with increased percentage of rice flour and maize meal. But the other pasting characters decreased with the higher proportion of rice flour. The baking absorption was observed to increase with higher level of maize meal but it decreased when level of rice flour was increased. Loaf weight (g) decreased with progressive increase in the proportion of maize meal but increased when rice flour incorporation was increased. Loaf volume, loaf height and specific volume decreased for progressively higher level of maize meal and rice flour. The sensory evaluation revealed that 25% replacement of wheat flour was found to be more acceptable than control sample.

Fractionation and grain hardness effect on protein profiling, pasting and rheological properties of flours from medium-hard and extraordinarily soft wheat varieties

In the present study coarse fraction (CF), medium fine fraction (MFF) and fine fraction (FF) were separated from flours milled from medium-hard and extraordinarily soft wheat varieties and were evaluated for various quality characteristics. Grain hardness of medium-hard and extraordinarily soft wheat varieties varied from 77 to 80 and 17 to 18, respectively. Ash and protein content was the highest for FF and the lowest for CF. Varieties with greater hardness produced higher CF and lower of FF. FF showed higher unextractable polymeric protein (UnEx-PP) and dough stability as compared to MFF and CF. FF showed lower damage starch content as related by lower Sodium SRC (NaSRC) as compared to MFF and FF. CF showed higher paste viscosities than FF and difference were greater amongst fractions from varieties with lower grain hardness. FF with greater proportion of small size particles showed greater accumulation of 98 kDa and 85 kDa PPs than CF. This study demonstrated that fractionation of flours can be employed to produce fractions with varied gluten strength required for production of various products.

Direct qualitative and quantitative determination methodology for massive screening of DON in wheat flour based on multi-molecular infrared spectroscopy (MM-IR) with 2T-2DCOS

Deoxynivalenol (DON) contamination in wheat flour induces a number of adverse health effects to consumers and livestock, even at very low concentrations. Direct detection methods for massive screening of DON in wheat flour is still lacking. A new methodology integrating multi-molecular infrared spectroscopy (MM-IR) with two-trace two-dimensional correlation spectroscopy (2T-2DCOS) was developed for in-situ qualitative and quantitative determination of DON in wheat flour as a whole. Typical spectral variation of wheat flour samples with diverse concentration of DON were stepwise characterized by MM-IR and tiny spectral profile differences resulting from concentration variation of DON were visually disclosed by 2T-2DCOS. Based on the obtained key spectral features of DON, 180 of wheat flour samples with DON higher and lower than 1.00 mg/kg were undoubtedly classified by Principal Component Analysis (PCA) and Support Vector Machines (SVM) with an accuracy rate up to 100% (for Second derivative spectra consisted of selected bands, SD-SS). Furthermore, a robust quantitative prediction model was established based on partial least squares (PLS) of SD-SS (Rc: 0.998, RMSEC: 0.135; Rp: 0.968, RMSEP: 0.421), and its excellent predictive capacity of model was validated by both residual prediction deviation (RPD) value of 3.2 and t-test. It was demonstrated that the developed methodology was applicable for screening and quantitative detection of DON in wheat flour based on the novel correlation analysis methods (SD-2DCOS-IR and 2T-2DCOS-IR) with chemometrics tools, which could be utilized both at laboratory and industrial level for quality control purposes of a large wheat flour sample set.

Analysis of wheat flour-insect powder mixtures based on their near infrared spectra

Insects are gaining more and more space in food and feed sectors, creating an intense scientific interest towards insects as food ingredients. Several papers deal with cereal-based products complemented by insect powder in the past few years. However, adulteration and quality control of such products present some hot topics for researchers, e.g., how can we justify the amounts and/or species of the insects used in the given products? Our paper aims to answer such questions by analysing seven edible insect powders of different species independently. The mixtures with wheat flour were analysed using near infrared spectroscopy and chemometric methods. Not only powders of different species were clearly differentiated, but also mixtures created by different amounts of wheat flour. Prediction of insect content showed 0.65% cross-validated error. The proposed methodology gives an excellent tool for quality control of insect-based cereal food products.