A. Derossi

Prevention of enzymatic browning in sliced potatoes by blanching in boiling saline solutions

The response surface methodology was applied to investigate the way in which variables, such as time of treatment, sodium or calcium chloride concentrations and lactic acid concentration, affect the blanching of potato slices in boiling solutions. Two 3 factor-5 level, second order central composite designs were developed to analyse the considered variables. Results showed that all the considered blanching treatments allowed polyphenoloxidase inactivation. With regard to colour, the use of calcium chloride, already at low concentrations, would seem better than the use of sodium chloride. Under the applied operative conditions, the best results were obtained with short times of treatment and low lactic acid concentrations.

A Review on Acidifying Treatments for Vegetable Canned Food

As is well known, pasteurization treatments are not sufficient for destroying heat resistance of spore forming microorganisms, which are prevented from germination and growing by pH reducing. So, the acidification process becomes one of the most important pre-treatments for the canning industry. It is commonly applied before pasteurization treatment with the purpose of inhibiting spore germination and for reducing heat resistance of the microorganism, thereby allowing to reduce the time or temperature values of the heat treatment. With the aim to reduce the pH of vegetables several techniques are available but their application is not easy to plan. Often, industries define operative conditions only on the basis of empirical experience, thus increasing the risk of microbial growth or imparting an unpleasant sour taste. With the aim of highlighting the correct plan and management of acidification treatments to reach safety without degrading quality of canned fruit and vegetables, the topics that are reviewed and discussed are the effects of low pH on heat resistance of the most important microorganisms, acidification techniques and significant process variables, the effect of low pH on sensorial properties, and future trends.

Changes in the aromatic profile of espresso coffee as a function of the grinding grade and extraction time: a study by the electronic nose system.

The changes in chemical attributes and aromatic profile of espresso coffee (EC) were studied taking into account the extraction time and grinding level as independent variables. Particularly, using an electronic nose system, the changes of the global aromatic profile of EC were highlighted. The results shown as the major amounts of organic acids, solids, and caffeine were extracted in the first 8 s of percolation. The grinding grade significantly affected the quality of EC probably as an effect of the particle size distribution and the percolation pathways of water through the coffee cake. The use of an electronic nose system allowed us to discriminate the fractions of the brew as a function of the percolation time and also the regular coffee obtained from different grinding grades. Particularly, the aromatic profile of a regular coffee (25 mL) was significantly affected by the grinding level of the coffee grounds and percolation time, which are two variables under the control of the bar operator.

Statistical Description of Food Microstructure. Extraction of Some Correlation Functions From 2D Images

Two algorithms able to compute lineal-path distribution function L(z) and two-point correlation function, S2(r1,r2) from 2D digital images of foods were developed and validated. Particularly, “Altamura” and “White” breads as well as “Napoli” sausages were studied. Lineal-path function was modeled by considering the foods as two-phase random systems composed from polydisperse overlapping disks. Instead, two-point correlation function was modeled by using a Debye’s equation. In all cases a good agreement between experimental and theoretical trend was obtained stating the high accuracy of the algorithms in the extraction of correlation functions as well as the possibility to model breads and sausages as two-phase random systems. Also, important morphological properties such as pores distribution, pore size homogeneity and their spatial distribution, were obtained. For instance, although the estimated radius of the pores was lower for “Altamura” bread rather that for “White”, its slowest decay of L(z) highlighted that the pores showed a high dimensional inhomogeneity.

The Application of Vacuum Impregnation Techniques in Food Industry

The interest of food scientists in the filed of microstructure is recently exponentially increased. This interest has raised after the recognition of the importance that chemical reactions and physical phenomena occurring at microscopic scale have on safety and quality of foods. This concept was well resumed from Aguilera (2005) which stated that “...the majority of elements that critically participate in transport properties, physical and rheological behavior, textural and sensorial traits of foods are below the 100 m range”. As example, Torquato (2000) reported that through microscopic observation it is possible to observe that only a portion of cells of the crumb bread solid matrix are connected, even though at macroscopic level it may appear as completely connected; so, the three dimensional spatial distribution of cell crumbs greatly affects the sensorial quality of bread. Before the scientific recognition of the above consideration, food scientists which focused their efforts on the effects of traditional and innovative industrial processes on food quality, analyzed only macroscopic indexes such as color, texture, taste, concentration of several nutritional compounds, etc. without to consider that they essentially are the result of chemical and physical phenomena occurring at microscopic level. However, with the aim to be more precise in the use of the term “microscopic” we may generalize the classification that Mebatsion et al. (2008) reported for the study of fruit microstructure. The authors considered three different spatial scales: 1. The macroscale which refers the food as a whole or a continuum of biological tissues with homogeneous properties; 2. The mesoscale which refers the topology of biological tissues; 3. The microscale which addresses the difference of individual cells in terms of cell walls, cell membranes, internal organelles, etc. Here, we would like focus the attention on the importance to study the foods at mesoscopic scale by considering them as mesoscopic divided material (MDM). On this basis the majority of foods may be defined as “biological systems where an internal surface partitions and fills the space in a very complex way”. At mesoscopic scale the three dimensional architecture of foods may be studied analyzing the relation between void and solid phases where the voids (capillaries, pores) may be partially or completely filled with liquids or gases. The relations between these two phases and their changes during processing is one of the most important factors affecting the safety and the sensorial and/or nutritional quality of foods. Until few years ago only the porosity fraction of foods was reported in literature as experimental index of the internal microstructure but it gives us only low level of information. Instead, a second level of

The study of acidifying blanching of pickled “Cicorino” leaves using Response Surface Methodology

Abstract Response Surface Methodology was applied to investigate variables such as concentration of citric acid in the blanching solution, time of treatment and number of recycles of the blanching solution, which affect the acidifying blanching of pickled “Cicorino” leaves. A Central Composite Design was developed to model the variables. Results showed that the obtained models were able to provide a good estimate of the effects of individual and interactive factors on the final pH of “Cicorino”. Among the considered factors, citric acid concentration is the main variable affecting sample pH value. The number of recycles did not affect in a negative way pH value providing an extension of the blanching time.

How the variance of some extraction variables may affect the quality of espresso coffees served in coffee shops.

BACKGROUND To improve the quality of espresso coffee, the variables under the control of the barista, such as grinding grade, coffee quantity and pressure applied to the coffee cake, as well as their variance, are of great importance. A nonlinear mixed effect modeling was used to obtain information on the changes in chemical attributes of espresso coffee (EC) as a function of the variability of extraction conditions. RESULTS During extraction, the changes in volume were well described by a logistic model, whereas the chemical attributes were better fit by a first-order kinetic. The major source of information was contained in the grinding grade, which accounted for 87-96% of the variance of the experimental data. The variability of the grinding produced changes in caffeine content in the range of 80.03 mg and 130.36 mg when using a constant grinding grade of 6.5. CONCLUSION The variability in volume and chemical attributes of EC is large. Grinding had the most important effect as the variability in particle size distribution observed for each grinding level had a profound effect on the quality of EC. Standardization of grinding would be of crucial importance for obtaining all espresso coffees with a high quality.

Use of Lineal-Path Distribution Function as Statistical Descriptor of the Crumb Structure of Bread

The importance of the relation between food microstructure and their quality is recognized as crucial. In terms of bread quality, the precise characterization of the crumb structure is considered essential to evaluate its sensorial properties. A variety of different statistical correlation functions have been theoretically formulated in recent years to quantify the microstructure of general random heterogeneous materials but they have rarely been applied in food science. In this paper, we have developed a method to calculate the lineal-path distribution function L(x) for the void and solid matrix phases from two-dimensional (2D) images of bread. The method has been successfully employed here to characterize the microstructure for two type of commercial breads. Our results reveal that crumb structure may be modeled as a system of polydispersed overlapping disks. Moreover, we have quantified the dimensions of the voids and crumb phase statistically and differences in the homogeneity of crumb structure.

On printability, quality and nutritional properties of 3D printed cereal based snacks enriched with edible insects

3D printing technology was employed to obtain snacks with a designed cylindrical geometry from wheat flour dough enriched by ground larvae of Yellow mealworms (Tenebrio molitor) as novel source of proteins. The main microstructural features, overall quality, and nutritional attributes were studied as a function of formulation, time and temperature of baking. The addition of ground insects up to 20 g/100 g (d.b.) resulted in softer dough. This caused an overflow in dough deposition producing the increase in diameter, height and weight of snacks. Baking conditions did not alter the overall aspect of the snacks, but modification of the main dimensional and microstructure attributes were observed due to the better water evaporation. The optimization of baking conditions found that 22 min and 200 °C allowed obtaining a maximum desirability of 0.693. Baked in these conditions, the printed snacks enriched with 10 and 20% of ground insects significantly increased the total essential amino acid, from 32.5 (0% insects) to 38.2 and 41.3 g/100 g protein, respectively. The protein digestibility corrected amino acid score increased from 41.6 to 65.2 from 0 to 20% insect enrichment, with lysine and methionine + cysteine being the respective limiting amino acid. Our results evidenced the rational promotion of insects based on nutritional arguments and validated the use of 3D printing as technology to manufacture innovative printed snacks without adverse impact on technological quality.

Study on Different Emulsifiers to Retain Fatty Fraction During Extrusion of Fatty Flours

ABSTRACT Doughs made from wheat and almond flours, water, and five types of emulsifiers commonly used in confectionary and bakery products (soy lecithin, sucrose esters, mono-glycerides, mono- and di-glycerides of fatty acids, and diacetyl tartaric acid esters of monoglycerides [DATEM]) were studied. To evaluate the additive ability to retain the fatty fraction during the extrusion process, electrical conductivity was measured and fat loss (%) that occurs during extrusion processing was determined. The electrical conductivity measurements showed that the lower and better concentration of soy lecithin and mixed mono- and di-glycerides of fatty acids to obtain an oil-water emulsion was 0.2 g/100 g of dough, while for sucrose esters and mono-glycerides of fatty acids, it was 0.7 g/100 g of dough. No efficacy for DATEM was observed. The fat loss results showed that sucrose esters were the most suitable emulsifiers for retaining the fatty fraction during extrusion processing, even at a very low amounts (2 g/kg...