Assessment of chalkiness index of Sake rice using transmission imaging.

The higher chalkiness level of the white core kernel is prone to breakage during the high degree polishing. So, grading white core kernel based on chalkiness level is crucial to making premium quality Sake (rice wine) in the brewing industry. The chalkiness level in the white core kernel is currently performed destructively. Thus, a chalkiness index is required to assess the level in the white core kernel. This research assesses the white core rice kernel based on the chalkiness index non-destructively. Here, the optical transmission property in the visible to near-infrared (VIS-NIR) region of rice was measured using a V-670 spectrophotometer equipped with an integrating sphere to investigate the variation of chalkiness level rice samples. The images were then acquired by transmission mode of four types of intact Sake rice kernel using blue light-emitting diodes (LEDs), green, red, and NIR LEDs in which the peak wavelength of the LEDs was 465 nm, 525 nm, 630 nm, and 830 nm, respectively. The result indicates that the rice samples were more penetrated and better visualized chalkiness by light in the NIR region. Therefore, the wavelength region in NIR showed better discrimination between transparent and opaque parts in white core's Sake rice. Furthermore, the proposed chalkiness index was inversely correlated with the gray-level intensity of the transmittance image. This gray value was significantly correlated (R2 = 0.89) with the chalkiness index in the NIR region. So, gray values of NIR transmittance images were identified as sensitive for chalkiness index, which would be applied for sorting the white core kernel with different levels of chalkiness in the Sake brewing industry.

Thermal oxidation assessment of Italian extra virgin olive oil using an UltraViolet (UV) induced fluorescence imaging system.

Extra virgin olive oil is a high-quality product with profound health benefits but is susceptible to degradation due to oxidation. Environmental conditions such as temperature, oxygen, and light, promote the oxidation process. From this perspective thermal oxidation stability is of primary concern in terms of food quality and safety. The ability to resist oxidation ensures continued nutritional and economic value. In this study, the thermal oxidation stability of four mono-cultivars of extra virgin olive oil from four different regions of Italy was studied. The samples underwent thermal treatment at 120 °C with measurements taken at regular time intervals over 180 min. To develop a simplified imaging system, the fluorescence characteristics of the samples during thermal exposure were measured using front-face fluorescence and transmittance spectroscopy in order to assess the changes that occur due to thermal exposure. Standard quality indices including; Peroxide value, acidity, K232, and K270, were also measured following IOC (International Olive Council) procedures. Image processing of both color and fluorescence images was done to ascertain cultivar responses to the thermal treatment. Fluorescence peaks associated with polyphenols, oxidation products, and chlorophyll were identified and monitored, and a comparison made between the different cultivars. Fluorescence peaks were observed at emission wavelengths 435, 465, and 570 nm, which are suspected to be products of oxidation and hydrolysis, respectively. The cultivars with a higher concentration of polyphenols showed greater resistance to the formation of oxidation products; an indication that they have a higher thermal stability. The B channel of the RGB color space was identified as being sensitive to changes in UltraViolet (UV) induced fluorescence images due to thermal exposure, and to enable the monitoring of the thermal stability of the different cultivars of extra virgin olive oil.