Role of dough viscoelastic properties and rice variety in the thermal expansion and the quality of unconventional rice-based bread: case of steamed-cooked ‘Ablo’

Ablo is a rice-based bread consumed in Southern Benin. We investigated the impact of pre-cooking conditions and starch characteristics on dough and Ablo physical properties. The solid-like behaviour of doughs measured by rheological sweep tests appears significantly negatively correlated to Ablo quality; above a starch gelatinisation level (7%–8%), the solid-like behaviour of the doughs increased sharply and the fluidity decreased, leading to Ablo of poor quality. A comparison between three rice cultivars tends to show that rice with low amylose content and/or gelatinisation temperature gives dough with higher fluidity and Ablo with lower density. In addition, a specific rheological test for measuring simultaneously dough expansion and rheological properties during heating has been developed. It shows that whatever the rice variety, thermal expansion of proofed dough begins and is followed by a dough/crumb transition. This innovative rheological test could be used for studying dough/crumb transition for other types of breads.     

Influence of lactic acid bacteria on the oxidation–reduction potential of buckwheat (Fagopyrum esculentum Moench) sourdoughs

The influence of lactic acid bacteria (LAB) growth on oxidation–reduction potential (ORP) of buckwheat sourdoughs was investigated. Sourdough fermentations are widely used for the production of bread and other bakery products. Until now the pH value is the most used control parameter taken into account during sourdough technology and no information is available about the influence of sourdough microbiota on the ORP or the use of redox potential (E _h7) measurements as a fermentation control parameter. The influence of growth and metabolism of lactobacilli on the oxidation–reduction potential of buckwheat (Fagopyrum esculentum Moench) sourdoughs was investigated. Upon inoculation with LAB, ORP changes were observed. Each strain exhibits a different ORP time course curve. The E _h7 after 8?h using Lactobacillus plantarum, Lactobacillus sakei, Weissella cibaria and Pediococcus pentosaceus reached 89.2?±?4, 104.5?±?15.3, 30.2?±?4 and 181.5?±?2.6?mV, respectively. W. cibaria showed the highest reducing activity and P. pentosaceus the lowest one. The maximal reduction rate was neither correlated with the highest acidification rate nor with the maximal growth rate. Nevertheless, the reduction rate shows a similar trend like the acidification rate during the time course of fermentation. The ORP changes occurred concomitantly with the acidification, and the acid production decreased after 2?h from the reducing step. These results showed the possibility to carry out ORP measurements in dough system. As strains exhibit very characteristic ORP curves, this parameter can be used as real-time control tool to monitor the time course of fermentation and metabolic activity. This enables an evidence-based determination of fermentation end and/or (intermediate) harvesting point, which is especially helpful in the development of new cereal fermentation types as in gluten-free sourdoughs.     

Impact of Legislature Regarding ‘Right to Food’ and ‘Wheat Fortification’ on Child Malnutrition: Cross-country Estimates

Food security objectives of UN Millennium Development Goals have been constrained by the lack of policy coordination in the spheres of food, nutrition and public health. This paper investigates the relative importance of coordination of nutrition legislation on malnutrition indicators. Using a regression analysis, the variation of incidence of stunting and under-five malnutrition for the year 2013 is explained using policy variables. Results reveal that low levels of implementation of ‘wheat fortification’ legislation and low level of constitutional support for food security result in statistically significant increments in malnutrition. Significant reductions in malnutrition are observable for highly coordinated implementation of both of these legislative articles. We control for anthropometric variables, income level and regional fixed effects in order to remove potential biases.     

Effect of pulsed electric fields – assisted extraction on anti-inflammatory and cytotoxic activity of brown rice bioactive compounds

The bioactive compounds of brown rice exhibit many beneficial health effects, ranging from antioxidant to cytotoxic activities. Pulsed Electric Field (PEF) pretreatment can significantly enhance their extraction, through the induction of the electro-permeabilization of the cell membranes.This paper aims to demonstrate that PEF-assisted extraction of brown rice enables not only enhanced yields of antioxidant compounds, such as γ-oryzanol, polyphenols and phenolic acids, and of saturated and unsaturated fatty acids, but also increased cytotoxic effects on cancer cells.Initially, the PEF-assisted extraction conditions have been defined by the assessment of the cell permeabilization index via impedance measurements and the DPPH antioxidant activity. Subsequently, the biological effects of PEF have been evaluated on the cytotoxicity and anti-inflammatory properties against human colon cancer cell line HT29.The results show that PEF-assisted extraction, enhancing the yield of bioactive compounds, with respect to untreated extracts, significantly promotes their antioxidant activity, which is correlated with an increased HT29 cells cytotoxicity. In addition, PEF extracts of brown rice substantially inhibit also gene expression and interleukin production in colon cancer cells, suggesting their exploitation as natural anti-inflammatory agents.The integration of PEF pretreatment in the solvent extraction process of bioactives from brown rice appears, therefore, as a promising practice to significantly enhance their biological activity.     

Give us today our daily bread: The effect of hunger on consumers’ visual attention towards bread and the role of time orientation

This study investigated the effect of hunger on consumers’ visual attention during a food choice task, and the role of time orientation (i.e., present and future orientation) in this interplay. A lab-based eye-tracking experiment including 102 participants was conducted, with hunger as the manipulated factor (hungry, satiated). Participants in the satiated condition were served a breakfast buffet before the experimental tasks, whereas participants in the hungry condition were served the buffet after completion of the tasks. Both groups were exposed to a set of planograms depicting supermarket shelves and were asked to choose an option they could consider buying, while their eye movements were recorded. Stimuli included non-food items as well as the key category of interest, Swedish crisp bread. After completion of the eye-tracking recordings, participants indicated their time orientation as well as their height and weight, which were used to calculate body mass index (BMI). The results revealed that hunger (vs. satiation) increased participants’ present orientation and visual attention towards bread, but decreased their future orientation, with participants’ present orientation mediating the effect of hunger on visual attention. Additional exploratory analyses revealed a positive correlation between participants’ BMI and their present orientation. Taken together, the results offer several fruitful avenues for future research, which may be used to promote public health. Moreover, the findings contribute to the literature by documenting that hungry individuals do not necessarily make more rapid decisions in drive-relevant domains; rather, they may actually devote a larger share of their attentional resources in the food domain, given their desire to acquire food.     

Effects of different vinification technologies on physico-chemical properties and antioxidant activity of ‘Falanghina’ and ‘Bombino bianco’ wines

The present research was aimed to compare the traditional white vinification with a combined cryomaceration–vinification in reductive conditions, by evaluating their effects on chemical and physical indices and on antioxidant compounds of ‘Falanghina’ and ‘Bombino bianco’, two wine grape cultivars of southern Italy. According to the results, the two cultivars showed similar behaviour in response to the same vinification protocol. The processing conditions mainly affected physico-chemical characteristics such as titratable acidity, pH, SO₂, tartaric and malic acids, phenolic concentrations, and antioxidant activity. Titratable acidity decreased with cryomaceration due to the tartrate precipitation, whereas the malic acid was greatly extracted from pulps and skins. In the reductive conditions applied, the SO₂ was protected by the presence of ascorbic acid; thus, the wines exhibited higher free/total SO₂ ratio. Cryomaceration combined with vinification in reductive conditions allowed a greater extraction of phenolic compounds from skins and, consequently, a greater antioxidant activity compared to the traditional winemaking. This behaviour was due to both the protection exerted by the low temperatures and the solubilisation of proanthocyanidins and flavans reactive with vanillin favoured by the high free SO₂ content.     

Influence of the soluble fibres inulin and oat β-glucan on quality of dough and bread

Bread represents a suitable food product for the addition of functional ingredients, such as the cholesterol-lowering dietary fibre oat β-glucan and the prebiotic inulin. Therefore, these soluble fibres were incorporated into wheat as well as gluten-free bread, and their effects on rheological properties of the dough, on bread quality and on crumb microstructure were compared. The level of remaining β-glucan as well as its molecular weight was determined using an enzyme kit and size-exclusion chromatography. The addition of oat β-glucan resulted in a higher water addition level, whereas incorporation of inulin had the opposite effect. Rheological testing showed that the incorporation of oat β-glucan results in a more elastic dough. The baking characteristics mainly affected by fibre addition were volume and crust colour, with inulin increasing and oat β-glucan decreasing loaf-specific volume in the gluten-free breads. Inulin led to a darkening of the crust of both bread types, whereas addition of oat β-glucan resulted in a lighter crust of gluten-free bread. Oat β-glucan softened the crumb of gluten-free bread, but had the opposite effect on wheat bread. Inulin resulted in an increased crumb hardness as well as the rate of staling. Beta-glucan breakdown was more pronounced in wheat bread than in gluten-free bread. The results show that the use of β-glucan to increase the nutritional value of wheat bread is limited due to negative influences on technological properties. However, this soluble fibre is highly suitable for incorporation into gluten-free bread.     

Effects of parboiling,storage and cooking on the levels of tocopherols,tocotrienols and γ-oryzanol in brown rice (Oryza sativa L.)

Vitamin E and γ-oryzanol display a wide range of biological activities including hypocholesterolemic, anti-inflammatory and antioxidant activities. Although white rice is far more popular worldwide, consumption of brown rice is increasing, partially on account of the presence of bioactive compounds; however, the effects of parboiling, storage and cooking on them are not well-characterized. The effects of parboiling and a 6-month storage period on the contents of vitamin E and γ-oryzanol in three brown rice cultivars grown in three different locations in Brazil were investigated. Also, their levels in branded non-parboiled and parboiled brown rice were monitored before and after cooking. Vitamin E homologues and γ-oryzanol were separated by RP-HPLC equipped with PDA and fluorescence detectors. The average levels of total tocols and γ-oryzanol in the raw brown rice cultivars studied were 25 and 188 mg/kg, respectively. Of the vitamin E homologues, γ-tocotrienol contributed with 74% of total tocols, followed by α-tocopherol, α-tocotrienol and γ-tocopherol in minor quantities. The combined processes, parboiling, storage and cooking, led to an approximate 90% reduction in tocols and only γ-tocotrienol was detectable after any of the processes. Parboiling followed by storage resulted in an approximate 40% loss of γ-oryzanol. Cooking had almost no further effect over γ-oryzanol levels in parboiled rice previously stored for 6 months.     

Prediction of panellists’ perception of bread crumb appearance using fractal and visual textural features

Ratings of visual characteristics of bread crumb images obtained by panellists were correlated with features obtained by digital fractal and texture analysis and simple thresholding. Trained panellists were asked to rate 168 bread crumb images on fineness, homogeneity and degree of orientation, using continuous line scales. The relative orientation of the main and secondary peaks of the image power spectrum was the only parameter related to the human perception of the degree of crumb orientation. Single fractal dimension terms correlated better with the panellists’ perception of grain fineness and homogeneity than the single crumb features from thresholding. Second-order polynomial models were significantly better (P < 0.01) in most predictors than simple linear models. Grain fineness was better approached by the method of relative differential box-counting fractal dimension (R ² = 0.822) whereas grain homogeneity was highly related to the mass fractal dimension (R ² = 0.820). Multiple linear models to estimate grain fineness with higher predictive capacity included predictors such as fractal dimension, mean intercellular distance and void fraction (R ² > 0.860).     

Effect of different β-glucans on the gelatinisation and retrogradation of rice starch

Four β-glucan preparations, i.e., curdlan (CL), oat (OG), barley (BG) and yeast (YG) β-glucans, were compared for their effects on the gelatinisation and retrogradation of rice starch (RS). Rapid visco-analysis (RVA) showed that addition of any of these β-glucans significantly increased the peak, breakdown, final, and setback viscosities of RS, whereas the pasting temperatures were significantly decreased by OG or CL addition, but were unaffected by BG or YG addition. Differential scanning calorimetry (DSC) demonstrated that all the β-glucans had a negligible effect on the onset (T_o), peak (T_p), and conclusion (T_c) temperatures but slightly decreased the gelatinisation enthalpy (△H₁) of RS. Storage of all the gels at 4 °C resulted in a marked decrease in the T_o, T_p, T_c, and melting enthalpy (△H₂) values. The retrogradation ratio (△H₂/△H₁) and the phase transition temperature range (T_c–T_o) of all the gels increased with storage time. Dynamic viscoelastic measurements revealed weak gel-like behaviour of all the gels, in which their storage modulus (G′) increased and their loss tangent (tan δ) decreased during storage. Steady flow tests illustrated time-dependent shear-thinning (thixotropic) behaviour of all the gels. The hysteresis loop area and the gel hardness increased with storage time. However, the rate and extent of retrogradation and the rheological and textural changes of the RS gels were reduced by addition of any of these β-glucans. The extent of the aforementioned effects differed among the different β-glucan preparations, generally in the order OG ≈ BG > CL ≈ YG.     

Effects of two barley β-glucan isolates on wheat flour dough and bread properties

The effects of wheat flour fortification with two different molecular weight barley β-glucan isolates (1.00 × 10⁵, BG-100 and 2.03 × 10⁵, BG-200) on the rheological properties of dough and bread characteristics, using flours from two wheat cultivars that differ in their breadmaking quality, have been examined. The farinograph water absorption of doughs and the moisture content and water activity of the breads increased with increasing β-glucan content; the β-glucan isolate with the higher molecular weight (BG-200) exerted a greater effect than did BG-100. The addition of β-glucans to the dough formula increased the development time, the stability, the resistance to deformation and the extensibility of the poor breadmaking quality doughs, as well as the specific volumes of the respective breads, exceeding even that of the good breadmaking cultivar. Furthermore, the colour of the bread crumbs got darker and their structure became coarser, whereas the bread crumb firmness decreased with increasing level of β-glucan addition. Generally, the BG-200 was more effective in increasing the specific bread volume and reducing the crumb firmness, especially when used to fortify the poor breadmaking quality flour. The results further indicate a requirement for optimisation of the fortified doughs (level and molecular size of the β-glucan) to maximise bread quality attributes (loaf volume, texture, and staling events).     

Effects of ‘energy’ drinks on mood and mental performance: critical methodology

Beneficial effects for mood and cognitive performance are believed to influence food and drink choice. The purpose of the present study was to demonstrate a sensitive methodology for providing objective evidence of such effects. A mildly fatiguing repetitive task formed the context for assessing the potential restorative effects of caffeine-containing ‘energy’ drinks. The methodology used was designed to account for a range of theorised variations in the data, many of which are often overlooked in current research. Significant effects of the energy drinks on task performance and self-rated mood were found. These effects can be summarised with the terms ‘alerting’, ‘revitalising’, ‘awakening’ and providing mental energy, and appear to be mainly caffeine related.     

Optimization of hydroxypropylmethylcellulose,yeast β-glucan,and whey protein levels based on physical properties of gluten-free rice bread using response surface methodology

Response surface methodology (RSM) was used to analyze effects of hydroxypropylmethylcellulose (HPMC), yeast β-glucan, and whey protein isolate (WPI) on physical properties of gluten-free bread baked from formulas based on rice starch. A Box–Behnken design with three independent variables (HPMC, yeast β-glucan, and WPI) and three levels was used to develop models for the different responses (physical properties). Individual contour plots of the different responses produced from the models were compared to the corresponding reference wheat bread data and were superimposed to locate gluten-free bread formulations that met the wheat bread standards for spread ratio, specific volume, hardness, cohesiveness, chewiness, and crumb color L∗ value. The optimal formulation, determined from the data, contained 4.35 g/100 g HPMC, 1 g/100 g β-glucan, and 0.37 g/100 g WPI, rice starch basis. Predicted values of the optimized bread were experimentally tested and compared with the experimental wheat bread data. A good agreement among these data was observed. Moreover, the optimized rice starch bread was found to be acceptable according to the results of sensory analysis.     

Non destructive detection of brown heart in ‘Braeburn’ apples by time-resolved reflectance spectroscopy

Brown Heart (BH) is an internal disorder which is visible only when fruit are cut open. The aim of this work was to test whether time-resolved reflectance spectroscopy (TRS) can be used to detect BH in intact ‘Braeburn’ apples stored for 3 and 6 months in BH inducing (1% O2 + 5% CO2) and not-inducing (2.5% O2 + 0.7% CO2) conditions. At each storage time, at d0 and d14 of shelf life at 18 °C, thirty apples were measured by TRS at 670 nm and in the spectral range 740-1100 nm on four points (A-D) around the equator. Afterwards, each fruit was cut open and evaluated for BH (position and severity), firmness, intercellular space volume (RISV), and pulp colour (in correspondence of TRS points). Fruit affected by BH showed significantly higher μa in the 740-900 nm spectral range than healthy ones, with the highest difference recorded at 740 nm. The μa740 and a* increased and L* and H decreased in fruit with moderate and severe BH and when BH was localized in the pulp. In parallel, RISV showed the lowest percentage in healthy apples and the highest when cavities were associated to browning. High correlations were found between μa740 and pulp L*, a* and H°; considering the correlation with L*, at μa740<0.038 cm−1 only healthy pulp can be detected, while at μa740>0.08 cm−1 only severely browned pulp can be found.