Evaluation of Color and Pigment Changes in Tomato after 1-Methylcyclopropene (1-MCP) Treatment.

The Polar Qualification System (PQS) was applied on hue spectra fingerprinting to describe color changes in tomato during storage. The cultivar 'Pitenza' was harvested at six different maturity stages, and half of the samples were subjected to gaseous 1-methylcyclopropene (1-MCP) treatment. Reference color parameters were recorded with a vision system colorimeter instrument, and the fruit pigment concentration was assessed with the DA-index®. Additionally, acoustic firmness (Stiffness) was measured. All acquired reference parameters were used to grade fruit in the supply chain. The applied 1-MCP treatments were used to control the ripening of climacteric horticultural produce. Both the DA-index® and stiffness values, presented as chlorophyll concentration and acoustic firmness, showed significant differences among maturity stages and treated and control samples and in their kinetics during storage. The machine vision parameter PQS-X was significantly affected by 1-MCP treatment (F = 10.18, p < 0.01), while PQS-Y was primarily affected by storage time (F = 18.18, p < 0.01) and maturity stage (F = 11.15, p < 0.01). A significant correlation was achieved for acoustic firmness with normalized color (r > 0.78) and PQS-Y (r > 0.80), as well as for the DA-index® (r > 0.9). The observed color changes agreed with the reference measurements. The significant statistical effect on the PQS coordinates suggests that hue spectra fingerprinting with this data compression technique is suitable for quality assessment based on color.

Lactic acid fermentation of apricot juice by mono- and mixed cultures of probiotic Lactobacillus and Bifidobacterium strains.

Apricot is a popular fruit in the world with rich in carbohydrates, vitamins and elements as well as has high antioxidant capacity. In this study, fermentation of this juice by mono- and mixed cultures was investigated. All tested strains exhibited good growth properties on apricot juice without any nutrient supplementation. In monoculture fermentation, 7.2, 7.25, 7.06 and 7.16 log (cfu/mL h) cell yields were observed for Bifidobacterium lactis Bb-12, Bifidobacterium longum Bb-46, Lactobacillus casei 01 and Lactobacillus acidophilus La-5 strains, respectively, and higher cell yields were obtained in the mixed culture fermentation. The antioxidant capacity increased slightly during fermentation. The concentration of acetic acid (27-48 mM) were about doubled in cases of the mixed culture fermentations than of monoculture fermentations (18-30 mM), while the levels of lactic acid were similar (70-90 mM). The relatively high values of these properties offer the potential for development of novel probiotic apricot juice.