Multivariate Analysis on the Properties of Intact Cereal Kernels and Their Association with Viscoelasticity at Different Moisture Contents.

The viscoelastic properties of cereal kernels are strongly related to their quality, which can be applied to the development of a more selective and objective classification process. In this study, the association between the biophysical and viscoelastic properties of wheat, rye, and triticale kernels was investigated at different moisture contents (12% and 16%). A uniaxial compression test was performed under a small strain (5%), and the increase in viscoelasticity at 16% moisture content corresponded to proportional increases in biophysical properties such as the appearance and geometry. The biophysical and viscoelastic behaviors of triticale were between those of wheat and rye. A multivariate analysis showed that the appearance and geometric properties significantly influenced kernel features. The maximum force showed strong correlations with all viscoelastic properties, and it can be used to distinguish between cereal types and moisture contents. A principal component analysis was performed to discriminate the effect of the moisture content on different types of cereals and to evaluate the biophysical and viscoelastic properties. The uniaxial compression test under a small strain and the multivariate analysis can be considered a simple and non-destructive tool for assessing the quality of intact cereal kernels.

Effect of the Addition of Different Vegetal Mixtures on the Nutritional, Functional, and Sensorial Properties of Snacks Based on Pseudocereals.

Quick meals available in markets are popular among consumers. Generally, these products are not recognized as functional foods owing to nutrient-poor composition. In this study, energy snack bars were developed with different formulations, using puffed quinoa, amaranth, cacao liquor, and coconut oil, and the effects of the addition of commercial vegetal mixtures (VM) on nutritional and functional properties were assessed. VM addition showed significant effects on the protein, lipid, and fiber contents, phenolic compounds (PHC) content, and antioxidant activity of the snacks. The control snack showed higher levels of free and bound PHC. The oxygen radical absorbance capacity (ORAC) analyses recorded highest values of free PHC (9392.7 µmol TE/100 g dry weight) in PC65 (concentrate based on a combination of vegetal proteins), whereas the highest bound PHC levels of 47,087 and 46,531 µmol TE/100 g dry weight were observed in PC65 and the control snacks, respectively. Sensorial attributes assessment provided a high score on the hedonic scale, wherein panelists detected no differences among the samples. Altogether, the selection of non-conventional ingredients with high antioxidant activities emerged as a successful strategy to produce sensory acceptable meals.

Recent Evidence of the Beneficial Effects Associated with Glucuronic Acid Contained in Kombucha Beverages.

PURPOSE OF THE REVIEW: Glucuronic acid is contained naturally in kombucha beverages due to the associations between bacteria and yeasts during its fermentation. The purpose of this review is to describe the literature related to the hepatoprotective effect associated with glucuronic acid present in different kombucha beverages. RECENT FINDINGS: Although previous research supports beneficial hepatoprotective effects of glucuronic acid consumption from kombucha, these effects are mainly attributed to the tea phytochemicals. However, there are some improvements in methodological deficiencies in some in vivo studies that should be considered. There is no sufficient evidence to generalize the adverse effects of kombucha consumption. Consumption of kombucha could be considered a safe practice in healthy populations due to its hepatoprotective effects. The content of the beneficial or toxic components is very variable because it depends on its manufacturing process. In persons with side sickness, other conditions such as pregnancy, and hypersensitivity to some kombucha components, a restriction in its consumption must be advisable.

Effect of Calcium Salts Concentration on the Viscoelastic Properties of Sintered Tablets from Flours and Tortillas Evaluated by Stress-Relaxation Tests.

This research aimed to evaluate the effect of different calcium compounds and their concentration on the viscoelastic parameters of flours and tortillas obtained with traditional and ecological nixtamalization. Specimens (tablets) of nixtamalized flours and tortillas (14% moisture) prepared with three different calcium sources and four concentrations were sintered using a die and a hydraulic press and were evaluated by stress-relaxation tests with a texturometer. Data collected from the stress-relaxation curve were fitted into a three-element generalized Maxwell model (r2 = 0.9999), allowing the detection of significant differences in the estimated viscoelastic parameters. When flours are processed into tortillas, the most notable change was the increase of +88.44% and +73.44%, respectively, in the summation of the elastic modulus, and the compressional viscosity in samples produced with CaCO3. On the contrary, tablets from samples with Ca(OH)2 presented a sharp diminishing (loss) in both of the evaluated viscoelastic parameters, accounting a decrease of -39.82% and -46.28% for the elastic modulus and compressional viscosity summations, respectively. Highly significant correlations were found among viscoelastic parameters when a slight proportional increase was observed in the specific elastic moduli, meaning that the energy was stored by each elastic element in the tablets, while the compressional viscosity coefficients varied as a function of time. Finally, it was found that the residual spring due to the pure elastic component (E0 ) stored energy during the entire test. PRACTICAL APPLICATION: There is no published information about a simple methodology for the evaluation of the viscoelastic properties of dry nixtamalized flours (powder) with a texturometer. The method proposed was sensitive and accurate, since it was capable of detecting differences among samples processed under distinct processing factors conditions. The study of viscoelastic properties of grain foods contributes to the construction of molecular theories occurring in their chemical compounds, which is strongly related to food texture. Those theories are handy to improve nutritional and textural properties of grain foods and are essential to powder handling, processing, and transportation, which allows the processing factors optimization.

Fumonisins and their analogues in contaminated corn and its processed foods - a review.

One of the food security problems faced worldwide is the occurrence of mycotoxins in grains and their foods. Fumonisins (FBs) are mycotoxins which are prevalent in corn (Zea mays L.) and its based foods. Their intake and exposure have been epidemiologically and inconclusively associated with oesophageal cancer and neural tube defects in humans, and other harmful health effects in animals. The toxic effects of FBs can be acute or chronic and these metabolites bioaccumulate mainly in liver and kidney tissues. Among FBs, fumonisin B1 (FB1) is the most relevant moiety although the 'hidden' forms produced after food thermal processes are becoming relevant. Corn is the grain most susceptible to Fusarium and FBs contamination and the mould growth is affected both by abiotic and biotic factors during grain maturation and storage. Mould counts are mainly affected by the grain water activity, the environmental temperature during grain maturation and insect damage. The abiotic factors affected by climatic change patterns have increased their incidence in other regions of the world. Among FBs, the hidden forms are the most difficult to detect and quantify. Single or combined physical, chemical and biological methods are emerging to significantly reduce FBs in processed foods and therefore diminish their toxicological effects.

Evaluation of visco-elastic properties of conditioned wheat kernels and their doughs using a compression test under small strain.

BACKGROUND: The aim of this research was to evaluate the visco-elastic properties of conditioned wheat kernels and their doughs by applying the compression test under a small strain. Conditioned wheat kernels and their doughs, from soft and hard wheat classes were evaluated for total work (Wt ), elastic work (We ) and plastic work (Wp ). RESULTS: Soft wheat kernels showed lower We than Wp , while the hard wheat kernels had a We that was higher than Wp . Regarding dough visco-elasticity, cultivars from soft and hard wheat showed higher Wp than We . The degree of elasticity (DE%) of the conditioned wheat kernel related to its dough decreased ∼46% in both wheat classes. The Wt , We and Wp from the soft wheat kernel and dough correlated with physico-chemical and farinographic flour tests. The Wt , Wp and the maximum compression force (Fmax ) of the dough from hard wheat class presented highly significant negative correlations with wet gluten. CONCLUSION: The visco-elasticity parameters from compression test presented significant differences among conditioned wheat classes and their doughs. © 2016 Society of Chemical Industry.

Obtaining ready-to-eat blue corn expanded snacks with anthocyanins using an extrusion process and response surface methodology.

Extrusion is an alternative technology for the production of nixtamalized products. The aim of this study was to obtain an expanded nixtamalized snack with whole blue corn and using the extrusion process, to preserve the highest possible total anthocyanin content, intense blue/purple coloration (color b) and the highest expansion index. A central composite experimental design was used. The extrusion process factors were: feed moisture (FM, 15%-23%), calcium hydroxide concentration (CHC, 0%-0.25%) and final extruder temperature (T, 110-150 °C). The chemical and physical properties evaluated in the extrudates were moisture content (MC, %), total anthocyanins (TA, mg·kg(-1)), pH, color (L, a, b) and expansion index (EI). ANOVA and surface response methodology were applied to evaluate the effects of the extrusion factors. FM and T significantly affected the response variables. An optimization step was performed by overlaying three contour plots to predict the best combination region. The extrudates were obtained under the following optimum factors: FM (%) = 16.94, CHC (%) = 0.095 and T (°C) = 141.89. The predicted extrusion processing factors were highly accurate, yielding an expanded nixtamalized snack with 158.87 mg·kg(-1) TA (estimated: 160 mg·kg(-1)), an EI of 3.19 (estimated: 2.66), and color parameter b of -0.44 (estimated: 0.10).