Federica Balestra

The Influence of Different Processing Stages on Particle Size, Microstructure, and Appearance of Dark Chocolate

UNLABELLED The effect of different process stages on microstructural and visual properties of dark chocolate was studied. Samples were obtained at each phase of the manufacture process: mixing, prerefining, refining, conching, and tempering. A laser light diffraction technique and environmental scanning electron microscopy (ESEM) were used to study the particle size distribution (PSD) and to analyze modifications in the network structure. Moreover, colorimetric analyses (L*, h°, and C*) were performed on all samples. Each stage influenced in stronger way the microstructural characteristic of products and above all the PSD. Sauter diameter (D [3.2]) decreased from 5.44 μm of mixed chocolate sample to 3.83 μm, of the refined one. ESEM analysis also revealed wide variations in the network structure of samples during the process, with an increase of the aggregation and contact point between particles from mixing to refining stage. Samples obtained from the conching and tempering were characterized by small PS, and a less dense aggregate structure. From color results, samples with the finest particles, having larger specific surface area and the smallest diameter, appeared lighter and more saturated than those with coarse particles. PRACTICAL APPLICATION Final quality of food dispersions is affected by network and particles characteristics. The deep knowledge of the influence of single processing stage on chocolate microstructural properties is useful in order to improve or modify final product characteristics. ESEM and laser diffraction are suitable techniques to study changes in chocolate microstructure.

Physico-chemical and metabolomic characterization of KAMUT® Khorasan and durum wheat fermented dough

Investigations were made in order to evaluate the influence of the flour type, chemical acidification and fermentation on characteristics of doughs obtained with durum wheat and KAMUT® Khorasan flour. Doughs were observed immediately after mixing, 90 and 360 min of leavening at 30 °C. Fundamental rheology, yeasts heat production by isothermal microcalorimetry and the interaction between water and biopolymers by means of time domain nuclear magnetic resonance were evaluated. In addition aromatic metabolite development was followed by means of the combined application of gas-chromatography and electronic nose. KAMUT® Khorasan flour was found to be more suitable than durum wheat for the fermentation processes tested, especially at acidic conditions, as shown by the increase of the volume and the metabolic heat production by yeast. In acidified dough the pattern of volatile metabolites allowed a clear distinction between the types of dough. Moreover the water/starch proton pool was characterized by higher T2 values in the KAMUT® Khorasan samples.

Effect of different new packaging materials on biscuit quality during accelerated storage

BACKGROUND The effect of innovative multilayer packaging materials versus a standard one on biscuit quality was studied during accelerated storage at 25, 35, 45 °C and 50% relative humidity for 92 days. Three different packaging materials were used: metalized orientated polypropylene (OPP)/paper (control); metalized poly-lactic acid (PLA)/paper; metalized OPP with ethylene vinyl acetate pro-oxidant additive (EVA-POA)/paper. EVA-POA additive is used to make the plastic layer biodegradable. Various quality sample parameters (moisture, water activity (aw ), texture, peroxide value (PV), hexanal) were analysed during storage. Rate constants (k) and activation energies (Ea ) of hydration reactions and hexanal formation were calculated. RESULTS No remarkable differences in the evolution of primary and secondary lipid oxidation were observed among differently packed biscuits during storage. All samples maintained PV levels between 4 and 14 meq O2 kg(-1) oil. The product in flexible packaging with PLA reached the highest moisture and aw levels, but they did not significantly and adversely affect the other quality characteristics. CONCLUSION The obtained results demonstrate that the new tested packaging materials were suitable for commercial biscuit storage, having similar performance and preservation effects on the overall product quality to those of the standard one. Furthermore, these results could make a contribution to the food industry, encouraging the use of packaging materials with a negligible environmental impact as an alternative to petroleum-based ones.

Influence of the addition of soy product and wheat fiber on rheological, textural, and other quality characteristics of pizza

The effect of partial replacement of wheat flour with soy paste and wheat fiber on rheological, textural, physicochemical, and organoleptic characteristics of an enriched pizza base (E) was investigated in comparison with those of a control pizza base (C). New ingredients (e.g., enriched cooked ham, whey cheese, and tomato sauce realized using food industry by-products) were also used in E pizza topping to further increase its nutritional properties. Enriched dough was developed first at a laboratory level. Large and small deformation, moisture, leavening activity, and metabolic heat were tested. On the final product, produced at the industrial level, textural, color, sensory, and nutritional analyses were performed. Preliminary rheological analysis was essential to evaluate the suitability of the new pizza to be processed at industrial level. Both pizza dough samples showed a solid elastic-like behavior; however, the addition of soy and fiber increased moisture content of E pizza, due to the water binding ability of soy protein and to the effect of fibers that also decreased E dough elasticity. No differences in extensibility between the two samples were observed, whereas significantly lower values of resistance to extension and dough force were shown in sample E. These differences were likely due to the presence of soy that interfere with gluten formation and to the dietary fibers that interact with water. Ingredients used in E pizza improved its nutritional quality increasing dietary fibers and protein, and decreasing saturated fatty acids and cholesterol content, which contributed to decrease energy value, in terms of kilocalorie reduction. PRACTICAL APPLICATIONS In this work, the effects of using new ingredients (e.g., soy paste, wheat fiber) on the rheological, textural, physicochemical, nutritional, and organoleptic characteristics of an enriched pizza type were investigated both at laboratory and industrial levels. The new pizza provides a product that combines solid technological performances, in terms of rheological properties and dough elasticity, with improved and balanced nutritional quality, thanks also to the ingredients used in the topping. Results demonstrate the possibility of obtaining new pizza products characterized by nutritional and sensorial properties tailored for different group of consumers.

Sensory and instrumental study of Taralli , a typical Italian bakery product

Taralli is a bakery snack food, typical of the south of Italy, that has currently become very popular worldwide as a savory snack or bread substitute. However, few studies have focused on its physical and sensory characteristics. The present work aims to select sensory and instrumental information that is able to characterize Taralli with similar formulation and size. For sensory characterization purposes, conventional profiling was applied on samples from different producers. All samples were also subjected to physical analysis of appearance and textural proprieties. Three samples of the set, differing only in storage time, were evaluated to assess changes in sensory characteristics during this period and a discrimination test (triangle test) was also applied for this purpose. The test results confirmed that the sensory analysis allowed a description of the entire range of characteristics resulting from stimulation of senses by physicochemical properties of the food. This methodology was effective in evaluating the quality characteristics and identify differences between Taralli samples during different storage times. Instrumental tests were also applied to assess food quality. The results revealed that a combined approach allowed obtaining more information about the product characteristics and definition of quality standards. This study also suggests the use of physical parameters obtained by simple and rapid instrumental tools can support sensory analysis, especially for evaluations that are fatiguing, when decisions made with the sensory data are critical or to provide objective reference standards that are suitable for training purposes.

Fermented Nut-Based Vegan Food: Characterization of a Home made Product and Scale-Up to an Industrial Pilot-Scale Production: Set up of fermented nut-based vegan food…

Because of the impossibility to consume food of animal origin, vegan consumers are looking for substitutes that could enrich their diet. Among many substitutes, fermented nut products are made from different nut types and obtained after soaking, grinding, and fermentation. Although other fermented vegetable products have been deeply investigated, there are few data about the fermentative processes of nut-based products and the microbial consortia able to colonize these products are not yet studied. This study characterized a hand-made vegan product obtained from cashew nut. Lactic acid bacteria responsible for fermentation were identified, revealing a succession of hetero- and homo-fermentative species during process. Successively, some lactic acid bacteria isolates from the home-made vegan product were used for a pilot-scale fermentation. The products obtained were characterized and showed features similar to the home-made one, although the microbiological hazards have been prevented through proper and rapid acidification, enhancing their safety features. PRACTICAL APPLICATION Spontaneous fermented products are valuable sources of microorganisms that can be used in many food processes as starter cultures. The lactic acid bacteria isolated in this research can be exploited by industries to develop new foods and therefore to enter new markets. The use of selected starter cultures guarantees good organoleptic characteristics and food safety (no growth of pathogens).