In Vitro Bioaccessibility Protocol for Chlorophylls

The daily ingestion of chlorophylls has been estimated at 50 g, but the knowledge about their bioaccessibility is limited. Different in vitro models have been utilized to estimate their potential bioavailability, but among other factors, the diversity of structures, chemical properties, and lability of chlorophylls hamper the investigations. By the first time, three extreme food matrices, one rich in fiber (vegetable puree), one rich in fat (virgin olive oil), and one liquid (fruit juice), have been assayed for chlorophyll bioaccessibility, controlling crucial variables. Chlorophyll polarity and food matrix were the determining factors, but surprisingly, chlorophyll bioaccessibility was affected during the application of the in vitro standardized protocol. Therefore, the present research has identified the reactions that can be biased during the estimation of chlorophyll bioaccessibility, defining a specific protocol in the function of chlorophyll structures.

Pyropheophytin a in Soft Deodorized Olive Oils

Mild refined olive oil obtained by neutralization and/or by soft deodorization at a low temperature and its blending with extra virgin olive oil (EVOO) is not allowed and is difficult to detect. Chlorophyll derivatives, pheophytins and pyropheophytin, and their relative proportions were proposed as parameters to detect such processes. The objective of this study is to determine changes in EVOO, in terms of pheophytins and pyropheophytin, occurring after several well-controlled mild refining processes. The changes on those chlorophyll pigments due to the processes depend on the temperature, stripping gas, acidity and oil nature. The data obtained show that, at temperatures below 100 °C, the rate at which pyropheophytin a is formed (Ra) is lower than the rate at which pheophytins a+a' disappear (Ra+a'). As a consequence, the Ra+a' and Ra ratios are considered to be directly linked to pheophytins a+a' decrease instead of to pyropheophytin a formation. Stripping gas very slightly affects the transformation of the chlorophyll pigments; actually both acidity and N2 enhance the increment in the Ra+a' and Ra ratios. In relation to the oil nature, the higher the initial pheophytin a+a' content, the higher the increase in the Ra+a' and Ra relations.

Does "best before" date embody extra-virgin olive oil freshness?

Virgin olive oil (VOO) decays in quality properties during aging, so aged VOOs may have detectable undesirable sensory descriptors in comparison with oils recently extracted. For that reason, freshness has become a parameter of paramount importance to maintain the highest standard levels within the period indicated in the "best before" date. However, it is important to note that freshness of VOOs is not necessarily related to its sensory quality. Pigments have been suggested for tracing aging of VOO, and pyropheophytin a (PPP) seems to be the most promising molecule for this task. A predictive model has been used to estimate %PPP in VOO stored at different worldwide locations characterized with different temperatures. The recorded average temperatures, on a monthly basis, were inputs of the predictive model. The results show the influence of temperature in %PPP and how this molecule could serve as a better monitor of the storage period of VOOs. The initial value of %PPP in the oil could help to carry out the storage traceability. This information would be of interest for producers, sellers, and inspection agencies.