Food Science and Technology International

The combined effect of natural antioxidants and packaging materials on the quality decay of breakfast cereals during storage was evaluated. Corn flakes were produced on industrial scale, using different packages and adding natural tocopherols to the ingredients, and stored for 1 year. The samples were then submitted to sensory analysis and HS-solid phase microextraction/gas chromatography/mass spectrometry (SPME/GC/MS) analysis. The packaging had a significant influence on the sensory profile of the aged product: metallized polypropylene gave the highest levels of oxidation compounds and sensory defects. The sensory profile was improved using polypropylene and especially high-density polyethylene. Natural tocopherols reduced the sensory decay of the flakes and the oxidative evolution of the volatile profile. They gave the most remarkable improvement in polypropylene (either metallized or not) packs. Polypropylene showed a barrier effect on the scalping of volatiles outside of the pack. This led to higher levels of oxidation volatiles and faster rates of the further oxidative processes involving the volatiles.

Instant noodles were prepared from fifteen diverse wheat cultivars varying widely in their flour quality and dough rheology. Dough thermomechanical parameters obtained by Mixolab and flour analytical properties were correlated with the quality of instant noodles including oil uptake, cooking quality and textural attributes. The Mixolab parameters dough development time and dough stability showed significant positive correlation with cooking time, cooked weight, overall acceptability, hardness, springiness, cohesiveness and chewiness of noodles, while negatively correlated with oil uptake and cooking loss, therefore, exhibiting a marked positive effect on quality of instant noodles. Lower protein breakdown represented by C2 torque was also positively related with overall acceptability, hardness, springiness, cohesiveness and chewiness of noodles. Stickiness/adhesiveness of noodles was revealed to be mainly conferred by falling number values (R²= 0.671) and damaged starch (R²= 0.523) content of wheat flour samples. Flour samples with lesser values of protein content, sodium dodecyl sulphate sedimentation volume, thermal stability of proteins, dough stability and dough development time were found to be linked with poor noodle quality. Medium strong flours performed better in noodle making, while weaker flours demonstrated poor noodle quality. Dough rheology of good noodle making flours was characterized with higher dough development time, dough stability, C2, C3, C4 as well as C5 values. Noodles with higher overall acceptability showed a more continuous and uniform protein starch matrix in comparison to the poor counterparts.

Peel pitting is a disorder occurring mostly during postharvest storage at non-chilling temperatures in different varieties of citrus fruit and consists in collapse of flavedo and albedo tissues that may affect oil glands. It has been demonstrated that during postharvest, sharp variations in water potential of cells from flavedo and albedo are sufficient to provoke fractures in cell walls from external albedo resulting in tissue collapse. However, morphology and composition of cells and cell walls in flavedo and albedo varies during fruit maturation and this may affect water flow through the different fruit peel layers and susceptibility of fruit to develop peel pitting. In this paper, we have studied the influence of the stage of maturation in the susceptibility of Navelina orange to develop peel pitting. Except in mature-green fruit, peel pitting increased with maturation after transferring fruit from 45% to 95% relative humidity and was also more severe as more dehydrated was the tissue before transference. Also, differences in water potential of fruit maintained at 45 or 95% relative humidity increased as fruit matured, suggesting that tissue reduces the ability of water adjustment during maturation. In this sense, only mature-green fruit flavedo was able to recover water potential when transferred from 45 to 95% relative humidity. Ethylene production upon transfer from low to high relative humidity increased only in mature tissue and was rapid and transient, and before initial symptoms of peel pitting. Flavedo and albedo water potential (ψ_w) was substantially reduced during fruit maturation. As lower was the ψ_w of freshly harvested fruit, minor variations were observed by changes in the storage relative humidity and higher the induced damage. Therefore, the increasing susceptibility of Navelina fruits to develop peel pitting with fruit maturation may be related to a reduced ability to regulate peel evapotranspiration and osmotic adjustment during postharvest storage.

In this study, the effects of ohmic pre-drying technique on moisture ratio, drying rate, drying time, specific energy consumption, drying efficiency, and effective moisture diffusivity of tomato paste were investigated. Pre-drying experiments were carried out in an ohmic laboratory dryer at voltage gradient levels of 6, 8, 10, 12, 14, and 16 V/cm and oven at 105 ℃ and 1.0 m/s air velocity (control sample). Pre-drying was accomplished till the moisture content of the tomato paste reduced from initial moisture content of 90% (w.b.) to a safer level of 70% (w.b.). The ohmic pre-drying reduced the drying time of tomato paste by 80–97%, compared with the hot air drying. Pre-drying took place mainly in warming up, constant rate, and falling rate periods. Six available moisture-ratio models were fitted to the pre-drying data. The results showed that the Midilli et al. model is the most appropriate model for pre-drying behavior of tomato paste. The effective moisture diffusivity varied from 5.39 × 10⁻⁸ to 3.91 × 10⁻⁷m²/s with an activation energy of 2.082 (V/g.cm). Both specific energy consumption and drying efficiency were considerably enhanced by increasing voltage gradient. It was found that the specific energy consumption and drying efficiency varied from 3.72 to 2.29 MJ/kg water and 67.8 to 83.8%, respectively.

Most of the commercialized lactic acid fermented products are dairy-based. Hence, the development of non-dairy fermented products with probiotic properties draws significant attention within the functional foods industry. The microorganisms used in such products have complex enzyme systems through which they generate diverse metabolites (volatile and non-volatile) that provide significant flavour attributes of importance for fermented foods. The correlation of the volatile flavour compounds of a malt beverage fermented with a Bifidobacterium breve strain with its unique sensory characteristics was performed. The volatile composition analysis exposed the presence of 12 components. Eight of these flavour volatiles were produced through the metabolic activity of the bifidobacteria strain. Notably acetic acid, of reported sour flavour characteristics, exhibited the greatest intensity. Four components of considerable organoleptic characteristics were identified as Maillard-derived products, namely maltol, pyranone, 2 (5H)-furanmethanol and 3-furanmethanol. The sensory evaluation exhibited that the fermented cereal beverage had a sour flavour with mild sweet and malty notes. These results indicate that the volatile compounds identified can be appointed as significant flavour markers of the novel fermented cereal beverage.

The objective of this study was to determine the lethal effectiveness of pulsed electric fields on the inactivation of the porcine blood endogenous microflora. Furthermore, the impact of pulsed electric field application on physico-chemical and sensory properties in this medium should be proved. Blood samples from a commercial abattoir in Germany were processed by a continuous pilot plant-pulsed electric field system at electric field strength of 11 kV/cm for treatment times of 163 and 209 µs. The applied pulse frequencies of 134 and 175 Hz correspond to an energy input of 91 and 114 kJ/kg, respectively. In these conditions, the effectiveness of pulsed electric field processing on microbial inactivation was limited: 1.35 log₁₀ CFU/mL reduction of total aerobic plate count (p < 0.05), 1.0 log₁₀ CFU/mL for Pseudomonas spp. (p < 0.05), 0.97 and 0.66 log₁₀ CFU/mL reduction for Enterobacteriaceae and sulfite-reducing anaerobic bacteria, respectively. However, the storage experiment (14 days at +3 ℃) showed a significant reduced growth of total aerobic plate count (p < 0.05) and Pseudomonas spp. (p < 0.05) in the pulsed electric field-treated blood samples. Pulsed electric field processing leads to a complete hemolysis of the red blood cells, in addition significant decreased L* (lightness), a* (redness) and b* (yellowness) values (p < 0.0001) were observed. Furthermore, changes in the sensory attributes color (changed from red to dark brown) and odor (changed from fresh to musty and tangy) were noticed.

Fresh-cut industry needs novel disinfectant to replace the use of chlorine. Ozone is one of the most powerful oxidizing agents and is applied in gaseous or aqueous form for sanitation purposes. However, the strong oxidative effect could affect the nutritional and sensorial quality, in particular, when time of washing is extended. For that reason, the overall impact of ozonated water (0.4 mg/L) dipping applied during 1, 3 and 5 min compared to control washed in water during 5 min was studied in tomato slices stored during 14 days at 5 ℃. According to the results, ozonated water treatment of 3 min achieved the best firmness retention, microbial quality (mesophilic, psychrotrophic and yeas load) and reduced the consumption of fructose and glucose. The use of ozonated water did not affect the total acidity, pH, total solid soluble, organic acid as ascorbic, fumaric or succinic acid and the sensorial parameters, which were only affected by storage time. However, the poor appearance, aroma and overall quality obtained in all treatments prevented shelf life of 14 days and the quality at acceptable levels was established in 10 days at 5 ℃. It is recommended to wash tomato slices with 0.4 mg/L ozonated water for 3 min only. Extending treatment duration did not improve the microbiological quality, possibly due to the extra time permitting the ozone to react with other components of the fruit tissue, undermining the antimicrobial benefits.