Influence of different blanching methods on colour, ascorbic acid and phenolics content of broccoli.

Lack of nutrients in cooking water, high energetic costs, high water consumption and recycling are some drawbacks of vegetable blanching. Those disadvantages could be bypassed using microwave blanching. Three blanching methods (microwave, boiling water and steaming) were compared in this study in order to determine their effects on some functional properties of broccoli. In addition, the thermal damage on broccoli colour was evaluated. The effectiveness of each blanching process was performed measuring the lost of peroxidase activity, that results more rapidly in microwaves and steam treatments (50 and 60 s respectively) than in boiling water treatment (120 s). The colour indexes did not allow to discriminate a significant difference among treatments. The increase of treatment time caused a vitamin C decrease in samples blanched by boiling water and steam; this trend was not observed in microwaved samples. The phenols content did not significantly vary depending both on type and on time of treatment.

Changes in the aromatic profile of espresso coffee as a function of the grinding grade and extraction time: a study by the electronic nose system.

The changes in chemical attributes and aromatic profile of espresso coffee (EC) were studied taking into account the extraction time and grinding level as independent variables. Particularly, using an electronic nose system, the changes of the global aromatic profile of EC were highlighted. The results shown as the major amounts of organic acids, solids, and caffeine were extracted in the first 8 s of percolation. The grinding grade significantly affected the quality of EC probably as an effect of the particle size distribution and the percolation pathways of water through the coffee cake. The use of an electronic nose system allowed us to discriminate the fractions of the brew as a function of the percolation time and also the regular coffee obtained from different grinding grades. Particularly, the aromatic profile of a regular coffee (25 mL) was significantly affected by the grinding level of the coffee grounds and percolation time, which are two variables under the control of the bar operator.

A review on acidifying treatments for vegetable canned food.

As is well known, pasteurization treatments are not sufficient for destroying heat resistance of spore forming microorganisms, which are prevented from germination and growing by pH reducing. So, the acidification process becomes one of the most important pre-treatments for the canning industry. It is commonly applied before pasteurization treatment with the purpose of inhibiting spore germination and for reducing heat resistance of the microorganism, thereby allowing to reduce the time or temperature values of the heat treatment. With the aim to reduce the pH of vegetables several techniques are available but their application is not easy to plan. Often, industries define operative conditions only on the basis of empirical experience, thus increasing the risk of microbial growth or imparting an unpleasant sour taste. With the aim of highlighting the correct plan and management of acidification treatments to reach safety without degrading quality of canned fruit and vegetables, the topics that are reviewed and discussed are the effects of low pH on heat resistance of the most important microorganisms, acidification techniques and significant process variables, the effect of low pH on sensorial properties, and future trends.

Autoxidation of packed almonds as affected by maillard reaction volatile compounds derived from roasting.

Shelled almonds of two Italian varieties, Romana and Pizzuta, peeled and unpeeled, were roasted and packed under different conditions: air (control), vacuum, and Maillard reaction volatile compounds (MRVc) derived from the roasting process. Samples were stored for approximately 8 months at room temperature, without light, and, at regular intervals, were collected and analyzed to evaluate the progress of lipid oxidation. Peroxide values, triglyceride oligopolymers, and oxidized triglycerides were evaluated during the storage time. Results showed that, although the MRVc atmosphere did not protect the lipid fraction of almonds as well as the vacuum condition; nevertheless, it was more protective than the control atmosphere, showing an antioxidant effect. The effect of the natural coating was a strong protection against lipid oxidation; in fact, only the unpeeled samples showed peroxide values lower than the threshold of acceptability (25 milliequiv of O(2)/kg of oil). Moreover, at the end of the storage period, Pizzuta almonds showed a greater deterioration than those of the Romana variety.