Lorenzo Fongaro

Ripening of salami: Assessment of colour and aspect evolution using image analysis and multivariate image analysis

During ripening of salami, colour changes occur due to oxidation phenomena involving myoglobin. Moreover, shrinkage due to dehydration results in aspect modifications, mainly ascribable to fat aggregation. The aim of this work was the application of image analysis (IA) and multivariate image analysis (MIA) techniques to the study of colour and aspect changes occurring in salami during ripening. IA results showed that red, green, blue, and intensity parameters decreased due to the development of a global darker colour, while Heterogeneity increased due to fat aggregation. By applying MIA, different salami slice areas corresponding to fat and three different degrees of oxidised meat were identified and quantified. It was thus possible to study the trend of these different areas as a function of ripening, making objective an evaluation usually performed by subjective visual inspection.

Wheat flour granulometry determines colour perception

Einkorn, durum wheat and Kamut® are rich of carotenoids, antioxidants with beneficial effects on human health. In the present study the effect of flour granule size on carotenoid content and colour was assessed; furthermore, the suitability of two colorimeters (Minolta Chroma meter CR-210 and Minolta Chroma meter II Reflectance), a spectrophotometer (Jasco V-650 with integrating sphere) and image analysis to define colour and determine carotenoid concentration in wheat flours of different granulometry was tested. Carotenoid content did not vary across flours of diverse size, except in the finest einkorn fraction (<80μm), which had lower concentration. For all instruments colour coordinate L* decreased and b* increased with flour size growth, while a* varied with the different devices. A Principal Components Analysis (PCA), performed considering carotenoid content and all colorimetric indices, distinguished einkorn from durum and Kamut®, and divided samples of different granulometry; a similar result was achieved by a PCA performed on the absorbance spectra from the integrating sphere. The PCA on image texture data classified the samples following flour size. In conclusion, flour colour is determined not only by carotenoid content but also by flour particle size: therefore, direct colour measurement seems not suitable to predict flour carotenoid content.

Gluten-Free Bread : Influence of Sourdough and Compressed Yeast on Proofing and Baking Properties

The use of sourdough is the oldest biotechnological process to leaven baked goods, and it represents a suitable technology to improve traditional bread texture, aroma, and shelf life. A limited number of studies concerning the use of sourdough in gluten-free (GF) breadmaking have been published in comparison to those on traditional bread. The aim of this study was to compare the properties of GF breads obtained by using a previously in-lab developed GF-sourdough (SD), compressed yeast (CY; Saccharomyces cerevisiae) or their mixture (SDCY) as leavening agents; more specifically, it aims to confirm the findings of a previous studies and to further improve (both in terms of recipe and process) the features of the resulting GF breads. Dough pH and rheological properties were measured. Fresh and stored breads were characterized for weight, height, specific volume, crust and crumb color, moisture, water activity, crumb hardness, and porosity. The combination SDCY was effective in improving bread volume and softness when compared to SD only. Furthermore, SD- and SDCY-crumbs exhibited a less crumbly behavior during storage (69 h, 25 °C, 60% of relative humidity) in comparison to CY-breads. This study confirms the positive effect of SD in GF breadmaking, in particular when used in combination with CY.

Effect of fresh pork meat conditioning on quality characteristics of salami

The aim of this work was to evaluate the effect of pork meat conditioning under different relative humidity (RH) values on salami quality characteristics. During a 6days conditioning period at 0°C under two levels of RH (95% vs. 80%), meat pH and weight loss were measured. Salami characteristics (moisture, weight loss, texture, appearance properties) were evaluated during 20days of ripening. Results showed that conditioning at 80% RH yielded a significantly drier meat, being the weight loss rate 1.6 times higher than at 95% RH. The lower water content of meat allowed a shorter salami ripening phase, guaranteeing an appropriate weight loss and the development of the desired texture, while maintaining good appearance properties. The acceleration of this production phase represents a clear economic advantage for producers and consumers, leading to higher profit margins and lower retail prices. The possibility of using FT-NIR spectroscopy as a valid tool for the rapid evaluation of salami ripening was also demonstrated.