Recently food-grade microemulsions have been of increasing interest to researchers and exhibited great potential on their industrial applications. The microbiological and quality characteristics of NuoMiGao, a traditional Chinese steamed rice cake, affected by a prepared food-grade monolaurin-containing microemulsion have been evaluated in this study. Microbiological analysis indicated that 0.05% microemulsion was comparable to 0.01% sodium dehydroacetate, extending the shelf-life by two days. The quality analysis showed that the addition of the microemulsion effectively prevented the hardening phenomena in rice cake; the lightness and yellowness were fairly stable while redness increased slightly (P<0.05); the lowered pH value and the prevention of moisture drop in rice cake were in agreement with the microbiological analysis and hardness trends.
Authors:J. Belovai, R. Romvári, H. Fébel, A. Szabó, and D. Bánáti
The n-3 fatty acids advantageously affect human health. Thus, partial substitution of pig backfat with soybean- or flaxseed oils in “Párizsi” (lyoner), with the aim to increase its n-3 fatty acid (FA) content, resulted improved FA profile (n-6/n-3 ratio). Relatively high (9% flaxseed oil) substitution decreased this ratio to the optimum (∼4). This modified FA profile was preserved during 32 storage days. Oil addition influenced fresh surface colour: lightness (L*) increased, redness (a*) decreased in parallel with the increasing oil addition, while only soybean oil increased yellowness (b*). Storage altered the colour slightly. The texture was not systematically altered by oil substitution, while during storage in a vapour permeable casing hardness increased. Considering organoleptic properties, soybean oil improved the extent of spiciness, while the general consumer acceptance was the most favourable (within complemented samples) by 3% flaxseed oil. Increasing vegetable oil levels intensified the taste of spice mixture.
Authors:M. Tomczyńska-Mleko, W. Gustaw, T. Piersiak, K. Terpiłowski, B. Sołowiej, M. Wesołowska-Trojanowska, and S. Mleko
The objective of the research was to obtain aerated gels by magnesium and iron(II) ion induced gelation of preheated whey protein isolate dispersions. Preliminary research allowed finding conditions of the pH, protein, and ion concentrations to produce aerated gels capable of holding air bubbles. A novel method applying gelation and aeration process simultaneously was used. Aeration using a laboratory mixer at 2000 r.p.m. produced stronger aerated gels than using a homogenizer at 8000 r.p.m. The gelation process was monitored using an ultrasound viscometer and a constant increase of dynamic viscosity was noted. A different aerated gel microstructure was observed for magnesium and iron(II) induced gels, which probably resulted in differences in the texture and viscosity, as well. The aeration process decreased hardness. In some cases texture parameters correlated with the viscosity measured using an ultrasound viscometer. Aerated whey protein gels could be applied as matrices for food applications or to controlled release of active ingredients.
Authors:A. Lambert-Meretei, E. Szendrei, M. Nogula-Nagy, and A. Fekete
The aim of the work was to develop a method to evaluate the effect of bread improver dosage on bread crumb texture. Standard breads were prepared to get different crumb structures when bread improver was added to the flour in a concentrate of 0.2%, 0.4% and 0.6%. The additive used in the experiments contains lecithin, ascorbic acid and alpha-amylase. Rheological tests and image analysis were performed to predict the effect of the additive. Hardness, chewiness, gumminess, cohesiveness and springiness were determined by rheological method. The rheological properties neither separately nor combined were able to discriminate the different bread crumb groups. Image processing method was developed to determine the ratio of dark to light area of the images taken of the bread slices. It was concluded that both rheological and visual parameters should be taken into account to characterize bread crumb texture.
Authors:M. Jridi, R. Siala, N. Fakhfakh, M.A. Ayadi, M. Elhatmi, M.A. Taktak, M. Nasri, and N. Zouari
The purpose of this study was to evaluate the effect of rosemary essential oil (250–1000 ppm) or its leaves (0.5–2%) on the quality of turkey sausage. The addition of essential oil had no significant effect on the sausage texture and colour parameters. A high rosemary leaves level resulted in an increase in sausage hardness and chewiness and a decrease in lightness (L*) with respect to the control sausage. Sensory evaluation indicated that rosemary essential oil and its leaves increased the taste and the aroma scores of turkey sausage depending on the concentration. The obtained results also showed that rosemary leaves (0.5%) were more effective than essential oil in reducing total plate counts, TBARS, K232, and K270 values during chill storage, in comparison with the control product. This will contribute to reducing the use of chemical additives, which are badly perceived by consumers, while increasing the sensory properties of such products.
In a 120 min osmotic dehydration procedure followed by an air drying process, the effect of carboxy-methyl cellulose (CMC) on some qualitative characteristics of apple slabs including browning index (BI) and rehydration capacity were studied. Moreover, the relation between textural and sensory properties, such as hardness, cohesiveness, springiness, adhesiveness and chewiness, was investigated. Samples containing higher coating concentrations (1–1.5%) showed higher rehydration capacity and lower browning index compared to those with lower coating concentrations (0.25–0.5%). Weibull distribution model was used to investigate the effect of coating concentration on drying kinetics. The results of sensory tests showed that the overall acceptance of samples is increased with decreasing coating concentration, and an appropriate correlation was found between sensory properties and textural parameters.
Authors:Y. Uchiyama, K. Ito, H. Li, Y. Ujihara, N. Kitabatake, and Y. Jean
The dependence upon concentration of sodium chloride of free volume in ovalbumin gels, a main component of an egg white, is studied by the positron annihilation lifetime technique. The average free-volume radius in ovalbumin gels was about 0.27 nm at 298 K, smaller than those of organic polymers such as low-density polyethylene (0.34 nm at 300 K) and polystyrene (0.29 nm at 300 K). These differences suggest that the positronium annihilates in free volumes located close to hydrogen bonds, thus decreasing average free-volume radius. Free-volume content decreased with the increase of NaCl concentration up to 30 mM. At lower concentrations of NaCl, it seems that a correlation exists between microscopic free volume and macroscopic hardness of the ovalbumin.
Authors:Tímea Kaszab, Lídia Bornemisza, and Katalin Badak-Kerti
flowing, and they have no yield stress. According to Foubert et al. (2006) and Gregersen et al. (2015a, 2015b) relationships between microstructure and macroscopic properties in coatings determine their flowing and textural properties (e.g. hardness
., Rousset M, Oury, F Faye A, Bar L ’Helgouac’h, C Lullien-Pellerin V. 2006. Grain characterization and milling behaviour of near-isogenic lines differing by hardness. THEOR. AND APPLIED GENETICS 114: 1–12.