Effects of polyols and nondigestible oligosaccharides on the quality of sugar-free sponge cakes

Interest in nutrition is driving consumer demands for less fat, sugar, and calories. In most foods, however, the removal or reduction of ingredients causes readily detectable losses in appearance, texture and mouthfeel. In this work seven bulking agents (maltitol, mannitol, xylitol, sorbitol, isomaltose, oligofructose and polydextrose) were used to totally replace sucrose in sponge cakes. The effect of this substitution on cake quality was determined by measuring texture, colour and volume after baking under controlled conditions. These parameters were established instrumentally and by sensory evaluation. Best results were obtained with xylitol and maltitol, leading to sponge cakes more similar to the control one – manufactured with sucrose – and with the highest acceptance level in sensory evaluations. Lower quality sponge cakes were those elaborated with mannitol.     

Improving gluten-free bread quality by enrichment with acidic food additives

An experimental design has been developed to improve gluten-free bread formulation, on the basis of rice flour and hydroxypropylmethylcellulose (HPMC) as alternative baking ingredients. In order to improve the quality of gluten-free bread, several levels of acidic food additives (acetic acid, lactic acid, citric acid and monosodium phosphate) have been tested. The influence of these compounds on the dough and on bread properties has been determined, including a hedonic sensory test of appearance, odour, taste and texture of bread. Results suggest that monosodium phosphate yields bread producing better texture scores, associated with the highest volumes of the loaf. Discussions are made on the basis of CO₂ transport pathway across the HPMC network and simultaneous interactions with acidic food additives present. Chemical properties of the acids justify the bread’s alveolus size and the preservative effects of acetic acid in the dough.     

Significance of healthy viscous dietary fibres on the performance of gluten‐free rice‐based formulated breads

The impact of associated viscous dietary fibres (hydroxypropylmethylcellulose semi‐firm – SFE‐ and weak – NE‐gel forming, and barley ß‐glucan, BBG) incorporated at different amounts (1.6–7.5%, flour basis) into gluten‐free rice‐based dough formulations on the breadmaking performance and staling behaviour of hydrated (70–110%, flour basis) fibre‐flour composite blends has been investigated. Single BBG addition fails to mimic gluten visco‐elasticity properly, but simultaneous incorporation of either SFE or NE contributes to bread improvement in terms of bigger volume and smoother crumb. 3.3 g of BBG (70% purity) and 104 mL of water addition to 100 g rice flour provided sensorially accepted breads (7.6/10) with a theoretical ß‐glucan content of 1.24 g per 100 g GF bread that would allow a daily ß‐glucan intake of 3 g provided a bread consumption of 240 g day^?1. Complementary tests should be carried out to know the amount and molecular weight of ß‐glucan in the final bread before assuring the nutritional benefit of this addition.     

Multivariate optimisation of a capillary electrophoretic method for the separation of glutenins. Application to quantitative analysis of the endosperm storage proteins in wheat

A capillary electrophoretic method has been designed to allow separation of glutenins with high resolution. Several factors, such as buffer composition, running voltage and capillary temperature were optimised using factorial design and response surface methodology. On the other hand, quantification of content of glutenins and gliadins of different wheat varieties were achieved for the first time using a glutenin extract of wheat gluten and a gliadin extract as external standards, respectively, and using the lys-tyr-lys tripeptide as internal standard. The optimised method and an early reported method for the gliadin separation were validated by evaluating linearity, sensitivity, detection and quantitation limits, repeatability and precision.     

Assessment of the microbiological conditions of red-meat carcasses from bacterial counts recovered by sampling via excision or swabbing with cotton wool

Samples from 240 carcasses were collected from four animal species (porcine, ovine, bovine and equine). Two samples were taken from each carcass, one using the excision method (EX) and the other the wet–dry swabbing method (SW). Eight areas from each carcass were sampled. Most of the samples obtained by SW revealed total aerobic viable counts (TVC) levels of between 3.1 and 4.0 log CFU cm⁻², while most of the values corresponding to excision were located between 4.1 and 5.0 log CFU cm⁻². Moreover, Enterobacteriaceae (EC) counts were only detected above 3.0 log CFU cm⁻² in 0.85% of the carcasses when the samples were collected by swabbing, while the excision method revealed that 13.75% of the carcasses presented EC greater than 3.0 log CFU cm⁻². TVC and EC by EX revealed statistically significant differences compared to SW, while no significant linear relationship was found between carcass surface bacterial counts obtained by SW and EX.     

Computational Study of Macroscopic Properties of Macromolecules with Industrial Interest

There is an increasing demand on the market for environmentally compatible lubricants. Refined vegetable oils have been used as biolubricants, but synthetic esters from renewable resources could also be considered as biolubricants, and can be prepared by combining different alcohols with linear or branched fatty acids. A tool has been developed to predict the properties of esters based on the chemical structure. A multilinear approach was used to correlate the experimental viscosity with theoretical parameters (diffusion coefficient, dipole moment and solvation energy) calculated from the expected chemical structure with a high degree of correlation.     

Long-term evaluation of a sequential batch reactor (SBR) treating dairy wastewater for carbon removal.

Many dairy industries have been using SBR wastewater treatment plants because they allow optimal working condition to be reached. However, to take advantage of SBR capabilities, strong process automation is needed. The aim of this work is to study the factors that influence SBR performance to improve modelling and control. To better understand the whole process we studied the kinetic modelling, the carbon removal mechanism and the relation between reactor performance, aerobic heterotrophic activity and bacterial population dynamics (by terminal restriction fragment length polymorphisms of 16S rDNA, T-RFLP). The heterotrophic activity values presented high variability during some periods; however, this was not reflected on the reactor performance. As sludge health indicator, the average activity in a period was better than individual values. Although all the carbon removal mechanisms are still unclear for this process, they seemed to be influenced by non-respirometric ways (storage, biosorption, accumulation, etc.). The variability of heterotrophic activity could be correlated with the bacterial population diversity over time. Despite the high variability of the activity, a simple kinetic model (pseudo ASM1) based on apparent constant parameters was developed and calibrated. Such modellisation provided a good tool for control purposes.     

Characterization of cake batters by ultrasound measurements

This work was undertaken in order to determine the feasibility of a low intensity ultrasonic sensor to be used in the control of the cake manufacturing process. A set of 27 batters with different oil, egg and sugar contents were elaborated to obtain products with different physical characteristics. The physical properties of batters (density, viscosity and rheology) and cakes (volume, symmetry, volume index, height and density) were correlated with ultrasonic measurements. Significant correlations were obtained between the acoustic impedance and the batter consistency (R² = 0.53), G″ (R² = 0.66), and G^* (R² = 0.53). The ultrasound measurement provided better correlations with physical properties of cakes than any of the conventional methods of batter measurement. This system has shown an interesting potential for industrial applications, especially in the detection of deficient batters.     

High-pressure liquid chromatographic determination of ascorbic acid in cooked sausages

The purpose of this paper was to study and optimize both extraction and high-pressure liquid chromatography (HPLC)-UV detection procedures to develop a proper method for the determination of ascorbic acid content in cooked sausages. A simple and sensitive reversed-phase HPLC method for the NH2-bonded phase has been described for the determination of ascorbic acid content in cooked sausages. Various extracting agents were tested to solubilize the vitamin, with 5% (wt/vol) metaphosphoric acid giving the best results. Samples were chromatographed with UV detection at 248 nm on a 25-cm Spherisorb NH2 cartridge with a 0.4-cm inside diameter with a mixture of 0.02 M potassium phosphate buffer solution (pH 3.6) and acetonitrile (40:60, vol/vol) for the mobile phase. The method's precision within a day was 1.2%, and its precision between days was 3.8%. The detection limit was 1.6 mg/100 g. Recovery ranged from 91.4 to 96.2% for ascorbic acid added to meat samples. Twenty samples of six different products were analyzed in duplicate. For the samples analyzed, the mean value for ascorbic acid ranged between 21.555 and 24.899 mg/100 g of fresh weight.