Safety and quality assessment during the ozonation of cloudy apple juice.

Traditionally, ozone processing within the food industry has focused on solid foods by either gaseous treatment or washing with ozonized water. However, with the FDA's approval of ozone as a direct additive to food, the potential for liquid applications has emerged. This study investigates the effect of ozone processing on microbial inactivation (E. coli ATCC 25922 and NCTC 12900) and quality parameters (color, phenolic content) of cloudy apple juice. Apple juice samples were ozonated at room temperature (20 ± 1.5 °C) with a generated ozone concentration of 0.048 mg O(3) at a constant flow rate of 0.12 L/min and treatment time of 0 to 10 min. E. coli inactivation kinetics in apple juice were described quantitatively by using the Shoulder log-linear and the Weibull model. Ozone treatment of E. coli in apple juice demonstrate that a desired 5 log reduction can be achieved within 5 min. Apple juice color (L*, a*, and b*) and total phenols were significantly affected by ozone concentration and treatment time.

Effect of storage on the content of polyphenols of minimally processed skin-on apple wedges from ten cultivars and two growing seasons.

In this study, the polyphenolic composition of skin-on apple wedges from ten cultivars was examined during chill storage and over two growing seasons. Individual polyphenol compounds were measured using HPLC resulting in the total polyphenolic index (TPI). Total phenolic content (TPC) was quantified using the Folin-Ciocalteu assay. Chilled storage had a significant effect (P < 0.001) on the polyphenol composition of all ten cultivars grown in 2007 and 2008. Total phenolic indices (sum of individual polyphenols) and TPCs of nine of the ten cultivars significantly decreased (P < 0.001) after 5 days of storage at 2-4 degrees C. These indices increased in case of Shampion apples over the same storage period. Changes in the most abundant compounds (-)-epicatechin, procyanidins and chlorogenic acid were largely responsible for changes in overall TPI. Percentage loss was higher for compounds such as phloridzin with a degradation of up to 100%. Irrespective of the different starting level of specific polyphenols in each year; storage resulted in a similar percentage loss/gain for each cultivar.

The optimization of extraction of antioxidants from apple pomace by pressurized liquids.

Pressurized liquid extraction (PLE) is a green extraction technique that can enhance extraction rates of bioactive compounds. PLE was used to extract antioxidants and polyphenols from industrially generated apple pomace at two different temperature ranges: 160 to 193 degrees C and 75 to 125 degrees C. Antioxidant activity (DPPH radical scavenging test), total phenol content and three individual polyphenol groups were determined. Response surface methodology was used to optimize the five response values. Maximum antioxidant activity was obtained at a temperature of 200 degrees C, but unwanted compounds such as hydroxymethylfurfural were formed. Therefore a lower temperature range between 75 and 125 degrees C is recommended. Using this temperature range, a maximum antioxidant activity was determined at 60% ethanol and 102 degrees C. By using PLE the antioxidant activity was increased 2.4 times in comparison to traditional solid-liquid extraction, and the technique may be a promising alternative to conventional techniques for extracting antioxidants.

Lignin degradation by Agaricus bisporus accounts for a 30% increase in bioavailable holocellulose during cultivation on compost.

The common mushroom Agaricus bisporus is a non-white rot saphrophytic fungus that can degrade lignin to free and utilize holocellulose embedded in fermented straw as present in compost. A new method is described to estimate the actual amount of bioavailable holocellulose in 3.8 kg compost cultures spawned with A. bisporus Horst U1 prior to and during a cultivation with two cycles of mushroom harvesting. The method shows that the initial amount of bioavailable holocellulose per culture, accounting for 130 +/- 22 g, is lower than the total holocellulose consumption by A. bisporus accounting for 182 +/- 15 g. This difference is explained by a 30% increase in bioavailable holocellulose. The increase is caused by the degradation of 95 +/- 3 g of holocellulose-shielding lignin. The results are discussed within the scope of the A. bisporus mushroom yield and lignin degradation by white rot fungi during growth on lignocellulose-containing materials.