Santina Romani

A novel fluorescence microscopy approach to estimate quality loss of stored fruit fillings as a result of browning

The aim of the present study was to estimate the quality deterioration of apple fillings during storage. Moreover, a potentiality of novel time-saving and non-invasive method based on fluorescence microscopy for prompt ascertainment of non-enzymatic browning initiation in fruit fillings was investigated. Apple filling samples were obtained by mixing different quantities of fruit and stabilizing agents (inulin, pectin and gellan gum), thermally processed and stored for 6-month. The preservation of antioxidant capacity (determined by DPPH method) in apple fillings was indirectly correlated with decrease in total polyphenols content that varied from 34±22 to 56±17% and concomitant accumulation of 5-hydroxymethylfurfural (HMF), ranging from 3.4±0.1 to 8±1mg/kg in comparison to initial apple puree values. The mean intensity of the fluorescence emission spectra of apple filling samples and initial apple puree was highly correlated (R(2)>0.95) with the HMF content, showing a good potentiality of fluorescence microscopy method to estimate non-enzymatic browning.

The influence of carrier material on some physical and structural properties of carrot juice microcapsules

This study investigates the effect of carrier type on the physical and structural properties of microcapsules of pure carrot juice. Low-crystallised maltodextrin (MD), gum arabic (GA), mixtures of MD and GA (1:1; 2:1; 3:1) and whey protein isolate (WPI) were used as carriers. Microencapsulation was carried out in a spray-drier at inlet air temperature of 160°C. Powders were investigated for dry matter, water activity, diameter, carotene content and hygroscopicity. In addition, differential scanning calorimetry (DSC) and time domain nuclear magnetic resonance (TD-NMR) were applied to analyse microcapsules glass transition temperature (Tg). Carrot powders with GA used as a carrier material resulted in better carotenoids retention and higher stability of powders in terms of higher Tg, lower aw and good hygroscopic properties. However, all powders showed a low aw (below 0.26) and high dry matter content (98-99%) indicating a good potential for protection of microencapsulated carotenoids during the storage.

Effect of freezing on microstructure and degree of syneresis in differently formulated fruit fillings

This study describes the syneresis and its effect on microstructure in fruit fillings within a wide range of the total soluble solids content and with or without hydrocolloids upon freezing. Linear models showed the relevance of the addition of pectin and gellan gum to fillings to prevent syneresis, increasing the water-holding capacity especially after freezing. Microstructural experiments by means of NMR spin-spin relaxometry combined with fluorescence microscopy allowed to observe that the continuous hydrocolloid gel, containing the dispersed solution of native fruit parts with the addition of inulin and sugars, changed its structure/distribution according to the amount of each ingredient and due to the freezing process. Relaxometry results confirmed that hydrocolloids strength was correlated (R(2)>0.92) with water-holding capacity, due to a relationship between the signal given by the water chemically exchanging with biopolymers, and the changes in the degree of syneresis.

Effects of chitosan based coatings enriched with procyanidin by-product on quality of fresh blueberries during storage

The aim of this work was to evaluate the efficacy of an innovative edible coating, based on chitosan from mushrooms enriched with procyanidins extracted from grape seeds, on fresh blueberry quality maintenance, (weight loss, pH, dry matter, colour, firmness and antioxidant activity) and microbial growth, during 14 days of storage at 4 °C. For weight loss, pH and dry matter no relevant differences were detected among the control and the differently coated samples at each considered storage time. Chitosan and chitosan + procyanidins coatings promoted a slight decrease of luminosity and an increase of blue hue colour of blueberry samples during the whole storage period. The use of coating promoted an increase in the antiradical activity that was the highest in blueberries coated with chitosan + procyanidins. Microbiological analysis results indicated that the chitosan-based coated samples had a significantly higher yeast and mould growth inhibition compared to the uncoated sample.

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.

Advances in Yield Stress Measurements for Chocolate

Chocolate (a cocoa dispersion), can be defined as a concentrated suspension made up of solid particles, such as sugar, cocoa powder, milk powder, etc., dispersed in a Newtonian liquid, generally cocoa butter. The rheological properties of this matrix are largely influenced by type and quantity of ingredients and processing techniques. During chocolate manufacturing, mixtures of sugar, cocoa and fat are heated, cooled, pressurized and refined. These steps not only affect particle size reduction, but also break agglomerates and distribute lipid and lecithin-coated particles throughout the continuous phase, thus considerably modifying the microstructure and so the yield stress of final chocolate products. The interactions between the suspended particles and the continuous phase provide information about the existing network and consequently can be associated with the properties and characteristics of the final dispersions. Since the macroscopic properties of chocolate products are strongly determined by their microstructure, the evaluation and study of the latter is very important, such as the application of adequate rheological models, to deeply understand the chocolate yield stress characteristics.

Bakery Products and Electronic Nose

Abstract The development of aroma in bakery products is due to a large number of volatile compounds resulting from enzymatic activity, fermentation, lipid oxidation, and thermal reactions during processing. In this chapter, the main electronic nose (e-nose) applications in bakery products, raw materials, and cereal grains are reviewed, as related to the main factors contributing to the formation, modification, and composition of volatile compounds. Different types of e-nose systems have been used to monitor and discriminate aroma compounds from different flours and ingredients, processing operations (such as baking), aging, and storage conditions. A greater number of e-nose applications are focused on the rapid discrimination of volatile compounds for early detection of microbial spoilage, being also associated to the presence of mycotoxins. Reported results prove that e-nose can be a rapid and sensitive mean for evaluating different quality aspects of bakery products and cereal grains.