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The aim of this work was to create an innovative sprayable bakery mix for foam-style cake preparation. The main goal was to obtain a batter liquid enough to be easily and quickly dosed in a spray system but maintaining its structure during baking. A commercial liquid batter was selected, and its recipe modified to fit in a spray system. The commercial bakery mix was characterized in terms of physical-chemical, thermal, and rheological attributes. The product was then diluted with milk or whipping cream at a 3:1 (gproduct/gdiluent) ratio to modulate its viscosity to be sprayed in a nitrous oxide loaded siphon system. All the prepared samples were characterized in terms of physicochemical properties at different stages of cake production (before and after spraying, and after baking) to investigate the effect of dilution on rheology and spray-ability and on the texture of final cake. Before cooking, the dilution determined an increase of water content and activity and a remarkable difference in colour coordinates compared to the reference.

Thermochemical and fractionation processes are promising ways for energy valorization and recovery of biomass and waste. An example is given by the application of a lignocellulosic fractionation process to recover both antioxidant phenolic compounds and cellulose from wheat straw, where a first hydrolysis step is carried out as a novel and green auto-hydrolysis process instead of conventional mild acid hydrolysis. Regarding this, the development of kinetic and reactor models that can represent the autohydrolysis process is crucial to exploit the potential of the agricultural residues (e.g., wheat straw). Several mathematical models were investigated, but the more suitable models for optimization purposes seem to be those based on a non-isothermal kinetic model. However, these models have several shortcomings. For instance, in the autohydrolysis process for the recovery of cellulose and lignin from by-products, the heating and cooling phases are not taken into account. Hence, from the point of view of energy optimization, closely linked also to economical optimization, this aspect becomes extremely important. Therefore, the aim of this work was to briefly present and comment, similarly to review work, the severity factor model and the kinetic model already investigated in the scientific literature in order to enable their comparison with the newly developed method in the current work in terms of different key performance indicators (e.g., cellulose recovery or sugar release). Specifically, our model includes new equations that consider both heating and cooling phases during autohydrolysis of wheat straw, as well as the isothermal step. In this way, it could be possible to use the obtained kinetic parameters not only for a specific case but also for different situations involving a wide range of operating conditions.

Frozen food sees a continuous increase in consumption thanks to the capability to preserve the organoleptic properties and, at the same time, to increase the shelf-life of the food itself. Therefore, a proper design of the freezing process is crucial and is strictly related to an accurate evaluation of freezing time because this establishes the minimum residence time of the product in a continuous freezer. For this reason, several mathematical models have been proposed and investigated for predicting the freezing time, starting from empirical models (lower accuracy and computational time) up to computational fluid dynamics simulation (higher accuracy and computational time). An excellent compromise between accuracy and computational effort seems to be a model that combines empirical laws for property evaluation and heat diffusion equation solved in one dimension. This model can numerically be solved using the method of lines in which spatial derivatives are discretized by the finite difference method and the resulting system of ordinary differential equations is integrated using an appropriate solver. This work aimed to fill some gaps to develop a comprehensive and more accurate model for freezing time prediction. Indeed, the key idea is to validate a model that could be used to optimize the refrigeration process for energy-saving and be the base for a design of experiment in case of lack of experimental data. The newly developed model includes the evaluation of freezing time for finite food shapes because, in some cases, it is not possible to assume a characteristic direction for heat flux. The property of unfrozen and frozen food (e.g. density, thermal conductivity, apparent specific heat, etc.) are evaluated basing on the principal constituent of food (e.g. water, fiber, protein, etc.), while heat transfer coefficient is evaluated using empirical equations, depending on adimensional numbers. In this way, it is possible to be flexible and not strictly related to the evaluation of the properties of food for each different case. The proposed model was validated with different sets of experimental data related to beef and strawberry pulp freezing. For these cases, the R2 index is equal to 0.982 and 0.996 respectively, showing a good agreement between experimental and predicted data. Finally, a case study of spinach cubes freezing was provided to show the potentiality of the novel model.

In this work sunflower oil (SFO) oleogels were obtained using rice bran wax (RBW) at 4.5 and 5.5% wt/wt. Bamboo fibre 40 µm (BF40) at 0.5% was investigated as structuring agent. The effect of fibre addition and cooling temperature (0, 4 and 25°C) on gel properties was evaluated compared to control samples prepared without fibre and at same cooling conditions. Rheological (both in rotational and oscillatory mode), texture and differential scanning calorimetry tests were carried out to assess thermal and structural parameters of gels. Oleogelatinization modified the rheological behaviour of samples, shifting from a typical Newtonian oil trend to a pseudo plastic non-Newtonian behaviour in gels. The gels resulted sensitive to temperature changes since a lower cooling temperature led to a structure weakening.

Thanks to their nutritional, healthy and sensory attributes, walnuts are raw materials of great interest for the agri-food sector. Nevertheless, a prolonged shelf-life is a fundamental requirement for promoting their industrial use. Rapid onset of rancidity can be avoided by adding preservative compounds and/or by applying stabilization processes able to make the fat component less prone to oxidation. The aim of this study was to evaluate the effect exerted by the addition of natural antioxidants (from grape skin) and/or by the application of an encapsulation technique on walnut paste. With the purpose of using them in bakery products, the developed formulations were subjected to thermal stress and used as ingredients in biscuits preparation: the impact of each treatment on fat fraction stability and antioxidant capacity was therefore assessed. In detail, walnut paste was obtained by roasting and grinding of kernels. An aliquot was enriched with 5000 ppm (w/w) grape skin extract in powder form. Both formulations were then encapsulated through a freeze-drying method, using maltodextrin DE12 and tragacanth gum as well materials. The chemical and oxidative analyses were performed on samples just after preparation, on the ones exposed to thermal stress (for 15 min at 180 °C) and on biscuits (baked at 180 °C for 15 min) that included just prepared samples. The results showed that the just prepared walnut paste supplemented with grape skin extract exhibited a greater antioxidant capacity, that was, however, reduced by heat treatment. Encapsulation procedure decreased the antioxidant capacity with a less evident effect on compounds revealed by FRAP and ORAC tests. The nutritional profile of just baked biscuits (intended as antioxidant capacity, phenolic profile, and tocopherol content) was not statistically influenced by the different formulations. In terms of induction period, encapsulated samples (and related biscuits) displayed higher values: the encapsulation process seemed to exert a barrier effect against oxidative agents and to protect the antioxidant properties of the grape skin extract, increasing the stability of both pasta and biscuits. In conclusion, recipe inclusion of encapsulated samples in just baked biscuits did not exert any benefits, neither in terms of oxidative stability, nor in terms of antioxidant properties. However, maltodextrins and gums, used as wall materials in the encapsulated samples, could help preserve the whole matrix prolonging the shelf-life of baking products containing them.

This study investigated the effect of the addition of three commercial dried sourdoughs containing different percentages of Saccharomyces cerevisiae (25-30%), on structural characteristics of wheat bread. Rheology, texture and physicochemical characteristics were assessed for both dough and final bread. Control samples were prepared using common dried bakery’s yeast (100% S. cerevisiae). The rheological parameters complex viscosity (?), linear viscoelastic region (LVR), storage and loss modulus (G’ and G’’) and angular tangent (tand) were evaluated on the doughs through rheological tests carried out both in rotational and oscillatory mode. Final breads were characterised for the texture profile (hardness, springiness, cohesiveness and resilience). Moisture content and pH were monitored during the process. The leavening agents (dried sourdoughs and bakery’s yeast) were characterized for the content of total lactic acid bacteria and total yeasts. Rheological analysis highlighted a pseudo-plastic behaviour for all the doughs with the elastic component prevalent on the viscous one (G’>G’’), without substantial differences among samples before proofing. After 3 h leavening, storage and loss moduli and complex viscosity were lower than control for all the sourdough samples. Microbial evaluation showed no vital lactic acid bacteria in the dried sourdough that, contrary to the other two, did not give acidification during leavening and produced a final bread with texture properties comparable to those of the control.

Walnuts are appreciated all around the world by consumers and food industries because of their different and positive properties including flavouring, texturizing and nutritional qualities. Walnut paste production and use are commonly associated to confectionery or traditional products but may find space in different innovative foods, as fat replacer and functional component. The aim of this work was to increase the nutritional value of walnut paste and, at the same time, limit its oxidative degradation by developing a freeze-drying process with addition of polysaccharide matrices including dietary fiber. The effects of different formulations and technological treatments on product stability were evaluated. Shelled walnuts were roasted at 165 °C for 15 minutes, grinded, and refined; the obtained walnut paste was mixed with betaglucan, inulin and pectin, singly or combined with tragacanth gum and DE12 maltodextrin. The different formulations were added to water, emulsified and dehydrated by freeze-drying. Lyophilized samples were finally stored at 60 °C for 15 days. Walnut paste, samples just after lyophilization, and lyophilized samples after storage were evaluated in terms of moisture, peroxide number, acidity and pH, conjugated dienes and trienes, total phenols and tocopherols. Further analyses (color, 410 and 420 nm absorption, and total phenols content after ethanol precipitation) were carried out on freeze dried samples before and after storage. The results showed that the freeze-drying process affected the nutritional profile of the walnuts, limiting the onset of oxidative phenomena. After storage the content of total phenols and tocopherols was significantly higher already in the freshly lyophilized walnut paste, compared to the untreated one. The addition of polysaccharide compounds aided to preserve total phenols. However, when betaglucan, inulin, or pectin were individually included, a significant depletion of tocopherols was observed. Maltodextrin and tragacanth gum played a fundamental role in maintaining high levels of both total phenols and tocopherols. Nevertheless, formulations including also dietary fiber were slightly more oxidized. Among them, the inclusion of betaglucan provided the overall best results.