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The sparingly soluble calcium hydrogenphosphate dihydrate, co-dissolving in water during dissolution of freely soluble sodium hydrogencitrate sesquihydrate as caused by proton transfer from hydrogencitrate to hydrogenphosphate, was found to form homogenous solutions supersaturated by a factor up to 8 in calcium citrate tetrahydrate. A critical hydrogencitrate concentration for formation of homogeneous solutions was found to depend linearly on dissolved calcium hydrogenphosphate: [HCitr2−] = 14[CaHPO4] - 0.05 at 25 °C. The lag phase for precipitation of calcium citrate tetrahydrate, as identified from FT-IR spectra, from these spontaneously formed supersaturated solutions was several hours, and the time to reach solubility equilibrium was several days. Initial calcium ion activity was found to be almost independent of the degree of supersaturation as determined electrochemically. The supersaturated solutions had a pH around 4.7, and calcium binding to hydrogencitrate as the dominant citrate species during precipitation was found to be exothermic with a determined association constant of 357 L mol−1at 25 °C for unit ionic strength, and ΔH° = −22 ± 2 kJ mol−1, ΔS° = −26 ± 8 J K−1 mol−1. Calcium binding to hydrogencitrate and, more importantly, to citrate is suggested to decrease the rate of precipitation by lowering the driving force of precipitation, and becoming important for the robust spontaneous supersaturation with perspectives for design of functional foods with increased calcium bioavailability.

The effect of working pressure, processing time, and salt addition on formation of free radicals in chicken breast and thigh muscle was investigated by electron spin resonance (ESR) spectroscopy using α-(pyridyl-1-oxide)-N-tert-butylnitrone (POBN) as spin trap in order to detect early events in lipid oxidation following high-pressure meat processing. Chicken breast and thigh with and without 3.0% salt added were subjected to high hydrostatic pressure at 200, 400, 600, 800, and 1000 MPa for 5, 15 (only breast), and 30 min. Radical formation increased with increasing pressure and processing time and reached a maximum value in chicken breast for 15 min of processing at 1000 MPa and in chicken thigh for 5 min of processing at 600 MPa. Radical formation was found to be more significant in thigh meat compared to breast meat and salt addition further promoted radical formation in chicken breast and especially in chicken thigh.The effect of working pressure, processing time, and salt addition on formation of free radicals in chicken breast and thigh muscle was investigated by electron spin resonance (ESR) spectroscopy using α-(pyridyl-1-oxide)-N-tert-butylnitrone (POBN) as spin trap in order to detect early events in lipid oxidation following high-pressure meat processing. Chicken breast and thigh with and without 3.0% salt added were subjected to high hydrostatic pressure at 200, 400, 600, 800, and 1000 MPa for 5, 15 (only breast), and 30 min. Radical formation increased with increasing pressure and processing time and reached a maximum value in chicken breast for 15 min of processing at 1000 MPa and in chicken thigh for 5 min of processing at 600 MPa. Radical formation was found to be more significant in thigh meat compared to breast meat and salt addition further promoted radical formation in chicken breast and especially in chicken thigh.

Abstract: The protective effect of rosemary (Rosmarinus officinalis L.) against lipid oxidation and tocopherol degradation in minced, pressure-processed chicken breast with 0.5% salt added was investigated during chill storage for 9 days and/or subsequent heat treatment by measurement of head-space hexanal and pentanal together with thiobarbituric acid reactive substances (TBARS) and α- and γ-tocopherol. High-pressure processing at 600 MPa for 10 min led to a significant increase in secondary lipid oxidation products in minced chicken breast without rosemary, when compared to chicken breast with rosemary added. During subsequent chill storage, the level of secondary lipid oxidation products decreased slightly. For samples heated after pressure treatment and chill storage to mimic cooking, levels of secondary lipid oxidation products were higher than for the uncooked samples and rosemary was very efficient in preventing the oxidative process also during cooking, while the length of the chill storage period prior to cooking had little effect. Higher levels of α- and γ-tocopherol were found in all samples with rosemary compared to samples without rosemary, indicating that rosemary also protects tocopherols against degradation in pressurized chicken breast during chill storage and/or subsequent heat treatment.

Dittany ( Origanus dictamnus L.) has been compared with rosemary ( Rosmarinus officinalis L.) as an antioxidant in pre-cooked meat balls made from chicken breast and added 0.50% salt during chill storage for up to ten days packed in atmospheric air. For an addition of 0.10% of dried leaves, dittany yielded protection of the product against oxidation a little less efficiently but comparable to dried rosemary added at the same concentration. For addition of 0.050%, dittany was less efficient than rosemary, while dittany at this concentration protected vitamin E against degradation in the product during storage even better than rosemary.

The effects of exposure of slices of Havarti cheeses to monochromatic light of wavelengths 366 nm, 405 nm, and 436 nm, respectively, were studied by tristimulus colorimetry, solid-phase microextraction gas chromatographic analysis of volatiles, and open-end fluorescence spectroscopy. Having determined the photon fluxes of the three wavelengths by ferrioxalate actinometry, it was possible to quantify the effects of light exposure in an absolute manner. For all analyses, the most severe effects were caused by visible light, leading to colour bleaching, change in hue, riboflavin degradation, and formation of the secondary oxidation products hexanal, 1-pentanol, and 1-hexanol. Apparent quantum yields for formation of hexanal and 1-pentanol were found to be insignificantly different for 405 nm and 436 nm exposures, having values of (3–5).10−5 mol.einstein−1 and (9–13).10−5 mol.einstein−1, respectively. These compounds were not formed when exposed to 366 nm light. In contrast, 1-hexanol was formed when exposing cheese to all three wavelengths, resulting in apparent quantum yields of (2–6).10−5 mol.einstein−1. The results obtained are discussed in relation to the interplay between inherent product colorants, light sources, and transmission characteristics of the packaging materials.

Abstract. The present study demonstrates that a rigid packaging material based on polylactate (PLA) was at least as effective as conventional high density polyethylene (HDPE) and polystyrene (PS) packaging materials in protecting fresh, unpasteurised orange juice against quality changes. Fresh, unpasteurised orange juice was stored in PLA, HDPE, and PS at 4 °C for 14 days. Quality changes were evaluated by determination of colour stability, ascorbic acid (AA) degradation, and sorption of limonene by the polymers (scalping). Results showed a significantly greater loss of AA in orange juice stored in HDPE and PS compared to PLA, significantly less colour changes of orange juice stored in PLA and PS than in HDPE, and no detectable limonene scalping into PLA and PS, as opposed to a high degree of scalping into HDPE.