Fei Tao

A nanosised oxygen scavenger: preparation and antioxidant application to roasted sunflower seeds and walnuts

A novel oxygen scavenger using iron nanoparticle was produced and evaluated as a potential oxygen scavenger. Iron nanoparticle was prepared by liquid phase reduction method in microemulsion systems. The absorption capacity of different kinds of oxygen scavengers was measured as a function of time, and the absorption rate constant was evaluated at 25°C. The absorption kinetic analysis showed that the absorption process followed a first-order reaction. The absorption rate constant of nanosised and conventional oxygen scavenger were 0.45±0.044h(-1) and 0.05±0.006h(-1), respectively. Successful application of the nanosised oxygen scavenger on roasted sunflower seed and walnut demonstrated its ability to inhibit lipid oxidation in lipid-containing food. Roasted nut treated with nanosised oxygen scavenger possessed the lowest PV and AnV in all treatments after 120 days of storage. Therefore, it has the potential for broad application as an active packaging in a variety of oxygen-sensitive foods.

Effect of hypobaric storage on quality, antioxidant enzyme and antioxidant capability of the Chinese bayberry fruits

BackgroundThe Chinese bayberry (Myrica rubra Sieb. and Zucc.) is a subtropical fruit native to China, with unique flavor, sweet and sour taste, and high nutrition and health values. The fruit is highly perishable and susceptible to mechanical injury, physiological deterioration and fungal decay once harvested. This study was to investigate the effect of hypobaric storage on the quality of Chinese bayberry fruit and then develop storage technology to prolong the supply of the fruit.ResultsThe fruit stored under hypobaric conditions exhibited lower decay, higher titratable acidity and total phenolics compared with those stored under normal atmospheric conditions. Hypobaric storage significantly reduced malonaldehyde accumulation, respiratory rate and maintained high catalase and peroxidase activities of Chinese bayberry fruit. Ferric reducing antioxidant power was also higher in the fruit stored under hypobaric condition than those under normal atmospheric conditions.ConclusionHypobaric storage improved the metabolism, antioxidant system and postharvest quality of Chinese bayberry fruit and provided an effective alternative method to prolong the storage life of this fruit.

Accumulation of lipofuscin-like pigments of walnuts (Carya cathayensis) during storage: potential roles of lipid oxidation and non-enzymatic glycosylation

BACKGROUNDnLipofuscin-like pigments (LFLP) are considered a hallmark of aging. The intracellular LFLP formation rate is negatively correlated with the life expectancy of cell. In food quality, increase of LFLP not only affects the appearance but also causes loss of nutritional value.nnnRESULTSnThe accumulation of LFLP increased during storage of all walnuts. LFLP fluorescent intensities of walnuts with 4%, 6%, 12% and 16% moisture at the end of storage were 8.1, 4.8, 4.3 and 2.8 times those at the beginning, respectively. The LFLP accumulation of walnuts with high moisture was found to be negatively correlated with soluble sugars and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical quenching rate, but positively correlated with the content of hydroxymethylfuraldehyde (HMF). While the LFLP accumulation of walnuts with low moisture had a strong positive correlation with anisidine value, it exhibited high negative correlations with acid phosphatase activity, DPPH(•) quenching rate and tocopherol content.nnnCONCLUSIONnIn walnuts with low initial moisture, lipoxidation products increased markedly during storage and these products might provide the source for LFLP accumulation. On the other hand, in walnuts with high initial moisture, reducing sugars derived from the hydrolysis of soluble sugars might play an important role in initiating the Maillard-like reaction, leading to LFLP accumulation.