A Novel Approach to the Study of Bread Porous Structure: Phase-contrast X-Ray Microtomography

ABSTRACT: The evaluation of bread quality can be carried out by performing a nondestructive investigation of its microstructure, which in turn can be performed by adapting image analysis techniques that enables one to obtain rapid, objective, and quantitative information. A suitable and reliable experimental methodology to investigate the porous structure of bread by means of the numerical image processing, and without any sample preparation, has been presented in this work. Different types of breads having varying degrees of porosity were studied by X-ray computerized phase-sensitive microtomography for the acquisition of digital high-resolution images. After acquisition, suitable numeric algorithms were applied to slice reconstruction. Finally, 3D images were rendered and analyzed.     

Assessment of chitosan and extracts of lemon and sage as natural antimicrobial agents during Fior di latte cheesemaking

The use of antimicrobial active compounds (chitosan, lemon and sage extract) in Fior di latte cheesemaking was assessed. The three agents were added at different concentrations during processing cow’s milk. Control cheese was also made without active compounds. All cheese samples were kept at 4°C for 7 days and investigated for sensory and microbiological properties. Results clearly showed that the addition of lemon extract and chitosan increased cheese shelf life. In particular, the highest increase (129%) was recorded by adding 1000 mg/kg of lemon. In contrast, the addition of sage extract negatively affected the sensory properties, thus making the cheese unacceptable.     

INFLUENCE OF DIFFERENT CASINGS ON SALAMI PRODUCED WITH MEAT FROM BUFFALO AND PODOLIAN CATTLE

ABSTRACT

The effect of different casings on the quality of new types of salami from buffalo and Podolian young bull meat was investigated. To this aim, three casings were used: a natural casing (NC), a modified natural casing (MNC) and a synthetic casing (SC). Their effects on processed meat were analyzed by evaluating salami quality at the end of the ripening time. Nutritional properties, microbial loads, pH, color parameters, texture and sensory properties were assessed. Moreover, the mechanical properties of the casings were measured. Results highlighted that both meat were suitable to produce salami; better results in terms of saturated and polyunsaturated fatty acids were recorded with Podolian meat. The NC and the SC exerted similar mechanical properties, very different from those of the MNC. The superior properties of the NC in terms of texture and color characteristics conferred to the fermented sausages could allow suggesting this casing as the most recommended solution to package unusual salami.

PRACTICAL APPLICATIONS

The increasing consumer interest in products with high energetic and nutritional value, authentic, tasty, rich in protein and low in lipid and cholesterol content gives rise to promote consumption of alternative meat to pork. Therefore, the influence of different casings on salami produced by boneless buffalo and young bull could be of crucial importance for industry that cares about consumer satisfaction.     

A New Approach to Predict the Water-transport Properties of Multilayer Films Intended for Food-packaging Applications

ABSTRACT: A mathematical model that predicts the water-permeability coefficient of multilayer films intended for food-packaging applications is presented. A 6-layer film composed of 5 polyolefinic layers and a layer made of a copolymer of ethylene and vinylalcohol (EVOH) was used to validate the proposed model. Water-permeability tests were run at 25°C both on each single layer and on the multilayer film; whereas the water-sorption isotherm and the water-sorption kinetics were determined only for the EVOH layer. Results suggest that the water-permeability coefficient of multilayer films can be predicted from the knowledge of the water-transport properties of each constituent layer.     

Maximum circumferential stress criterion applied to orthotropic materials

The topic of the paper is the extension of the Maximum Circumferential Tensile Stress Criterion to orthotropic materials, to obtain the crack initiation angle and the fracture loci. It includes the effects of orthotropy, load biaxiality and non‐singular terms. It requires the solution of the elastostatic problem of an orthotropic plate having a central inclined crack and subjected at infinity to a uniform biaxial load. It is assumed that the crack line does not coincide with an axis of elastic symmetry of the body. The original problem has been transformed by rotation into a system of coordinates with one axis along the crack. The effects of the rotation of the reference system on the stress–strain equations as well as on the equilibrium equations have been considered. The stress field is represented in terms of two potential functions and the crack problem is solved by means of the superposition principle.     

Prediction of residual fatigue life of aluminium foam through natural frequencies and damping shift

This paper deals with the application of a non-destructive technique based on natural frequencies and damping evaluation to predict fatigue failure of closed cell aluminium foams. Two different numerical methods have been used to analyse data, and a detailed analysis about frequency and damping evolution of metallic foam specimens subjected to fatigue load is shown. Moreover, significant correlations between modal data changes and the evolution due to the relevant fatigue loads in the high-cycle regime have been extracted; these correlations may be efficiently used to predict the residual life with good accuracy from the beginning of the fatigue tests.     

LEMON EXTRACT AS NATURAL PRESERVATIVE IN FRUIT SALAD

In this study the feasibility of using lemon extract to preserve the microbial quality of fresh fruit salad is addressed. In particular, two different packaging strategies were tested: lemon extract directly dissolved into the fruit solution and lemon extract dissolved into a gelatin that was put at the bottom of the salad tray. The microbiological quality decay kinetic of the differently packed cut fruit, stored at 4C, was determined by monitoring spoilage microorganisms for about 20 days. Results show that the active gel in the packaged fruit salad does not seem to affect to a great extent the growth of the investigated microorganisms; on the contrary, the use of the active solution seems to be effective in inhibiting the growth of the natural spoilage microflora, preserving the microbial quality of the packaged product for a longer time.

PRACTICAL APPLICATIONS

The results obtained in this research could be advantageously used by industry as a request of consumer demand for high-quality convenience food. The present research represents a starting point to develop high safety packaging systems able to prolong the shelf life of fresh cut fruit. Encouraging results on the use of natural products to control postharvest rotting indicate that it is possible to substitute the synthetic compounds with preservatives safer for man and environment.