Alessandro Giunchi

SHELL EGG ALBUMEN HEIGHT ASSESSMENT BY FT-NIR SPECTROSCOPY

Fourier transform near-infrared (FT-NIR) spectroscopy was used for quantitative measurements of thick albumen height. By means of a fiber optic probe in direct contact with the shell, non-destructive acquisitions by diffuse reflectance were carried out to establish a model to predict this egg quality index. After breaking the egg and measuring the reference parameter albumen height, transmission acquisitions of the thick portion of the albumen were also performed. The predictive models obtained from the two experiments showed a good correlation in terms of coefficient of determination (R2 = 0.819 for non-destructive analysis, and R2 = 0.764 for transmission measurements) between the spectral data and the thick albumen height. In both cases, about 80% of the eggs that were not used for model development were predicted with a maximum error of ±1 mm.

Physical-Mechanical Modifications of Eggs for Food-Processing During Storage

Physical-mechanical properties of egg constituents and their modifications during storage and poststorage greatly influence the efficiency of food processing, such as the separation of white and yolk by mechanical shelling. Thick albumen height, Haugh unit, yolk index and vitelline membrane-yolk system strength of eggs from Hy-Line White and Lohmann Brown hens were analyzed during 7 mo of storage at 0 degrees C performing 3 poststorage treatments: i) immediately after refrigeration, T1; ii) after a further 6 h at 18 degrees C after refrigeration, T2; and iii) after a week at 18 degrees C after refrigeration, T3. For all qualitative parameters considered, this last poststorage treatment appeared to be the factor that produced the highest decrements; with respect to the first poststorage treatment, a further week at 18 degrees C after refrigeration can involve mean decreases of about 19, 14, 14, and 16% in thick albumen height, Haugh unit, yolk index, and vitelline membrane-yolk system strength (in terms of maximum force), respectively. During about 7 mo of storage at 0 degrees C, the latter parameter decreases, on average, by 10%. Increasing the storage time, physical-mechanical behavior was sometimes divergent from the observed trends.

FT-NIR spectroscopy for the quality characterization of apricots (Prunus armeniaca L.).

UNLABELLED The nondestructive assessment of apricot fruit quality (Bora cultivar) was carried out by means of FT-NIR reflectance spectroscopy in the wavenumber range 12000 to 4000 cm⁻¹. Samples were harvested at four different ripening stages and scanned by a fiber optical probe immediately after harvesting and after a storage of 3 d (2 d at 4 °C and 1 d at 18 °C); the flesh firmness (FF), the soluble solids content (SSC), the acidity (A), and the titratable acidity (malic and citric acids) were then measured by destructive methods. Soft independent modeling of class analogy (SIMCA) analysis was used to classify spectra according to the ripening stage and the storage: partial least squares regression (PLS) models to predict FF, SSC, A, and the titratable acidity were also set-up for both just harvested and stored apricots. Spectral pretreatments and wavenumber selections were conducted on the basis of explorative principal component analysis (PCA). Apricot spectra were correctly classified in the right class with a mean classification rate of 87% (range: 80% to 100%). Test set validations of PLS models showed R2 values up to 0.620, 0.863, 0.842, and 0.369 for FF, SSC, A, and the titratable acidity, respectively. The best models were obtained for the SSC and A and are suitable for rough screening; a lower power prediction emerged for the other maturity indices and the relative predictive models are not recommended. PRACTICAL APPLICATION The results of the study could be used as a tool for the assessment of the ripening stage during the harvest and the quality during the postharvest storage of apricot fruits.

MECHANICAL BEHAVIOR AND DAMAGE OF PINK LADY APPLES

Research was conducted to investigate the type of damage and mechanical behavior of Pink Lady apples during post-harvest operations. Samples of apples of this new cultivar were subjected to drop tests to simulate the kind of impact recorded in Italian sorting and packing lines by means of an instrumented sphere. A simple device with an acceleration transducer mounted on the apple and an acquisition system were used to cause an impact and to describe the mechanical behavior of the fruit. Data were treated statistically employing logistic regression and multiple linear regression analyses to determine correlations between probability, characteristics of damage and parameters describing impact and characteristics of the apples. A logit model was used to assess the probability of damage occurring to fruit. In this model (R2 L = 0.380) the characteristics of the impact and the firmness of the flesh of the fruit were found to be significant. The kind of damage appeared to be significantly influenced by the impact level and, in general, by the mass, the sugar content and the curvature radius at the point of impact on the apples. Coefficients of determination of the models to predict characteristics of damage were from 0.104 to 0.312. The curvature radius was correlated with peak acceleration of the apples, too (R2 = 0.210). Although the prediction power of the statistical models was low, they were useful to check significance and analyze correlations between parameters.