Quality of oil extracted by cold press from Nigella sativa seeds conditioned and pre-treated by microwave.

Black cumin (Nigella sativa) seed (BS) oil has received much interest in the food and pharmaceutical industries due to its valuable nutritional properties, but this oil has low oxidative stability. The effect of microwave pre-treatment at 0 to 2.5 min and conditioning with different buffers at pH 3 to 9 of BS, before oil extraction by cold press, were investigated. The oil extraction yield was higher; acid value (AV) and peroxide value (PV) were lower in the oil extracted from seeds, which were first microwaved and then moisturized and vice versa. BS with pH 3, microwave time of 1.25 min, and moisturizing level of 5%, which gave oil extraction yield of 27.2%, AV of (2.9 mg NaOH/g oil), and PV of (8.3 meq O2/kg oil), was selected as an optimum sample and its quality changes were investigated during storage compared with the oil extracted from the control sample (without any pre-treatment). In conclusion, the oil extracted from the pre-treated BS had higher bioactive components and lower AV and PV during the storage; therefore, microwave radiation and pH adjustment before oil extraction from BS by cold press are recommended.

Improving the thermal stability of natural bioactive ingredients via encapsulation technology.

Bioactive compounds (bioactives) such as phenolic acids, coumarins, flavonoids, lignans and carotenoids have a marked improvement effect on human health by acting on body tissues or cells. Nowadays, with increasing levels of knowledge, consumers prefer foods that can provide bioactives beside the necessary nutrients (e.g., vitamins, essential fatty acids and minerals). However, an important barrier for incorporating bioactives into foods is their low thermal stability. Nevertheless, thermal processing is widely used by the food industries to achieve food safety and desired texture. The aim of this work is to give an overview of encapsulation technology to improve thermal stability of bioactives incorporated into different food products. Almost all thermal analysis and non-thermal methods in the literature suggest that incorporation of bioactives into different walls can effectively improve the thermal stability of bioactives. The level of such thermal enhancement depends on the strength of the bioactive interaction and wall molecules. Furthermore, contradictory results have been reported in relation to the effect of encapsulation technique using the same wall on thermal stability of bioactives. To date, the potential to increase the thermal resistance of various bioactives by gums, carbohydrates, and proteins have been extensively studied. However, further studies on the comparison of walls and encapsulation methods to form thermally stable carriers seem to be needed. In this regard, the same nature of bioactives and the specific protocol in the report of study results should be considered to compare the data and select the optimum conditions of encapsulation to achieve maximum thermal stability.

Practical application of nanoencapsulated nutraceuticals in real food products; a systematic review.

In recent decades, due to the increase in awareness, most consumers prefer foods that not only satisfy their primal urge of hunger but also include health-promoting effects on the body. Therefore, the food industry has an increasing tendency to apply the nutrients (like vitamins, essential fatty acids and minerals) and replace synthetic additives with natural bioactives (like phenolics and essential oils) to produce functional products. However, low dispersibility and shelf-stability as well as presenting unpleasant taste and odor are the most critical barriers for direct incorporation of these useful compounds into foods. In this context, nanoencapsulation has been proposed as a relatively new solution to overcome the mentioned limitations. However, fewer studies have focused on incorporating the bioactive-loaded nanocarriers into the food matrices. This study intends to help the development of functional food production by doing an exhaustive review on the incorporation of nanoencapsulated ingredients into the real food system and resulted interaction of nanocarriers and food products. According to the literature, incorporation of the nanoencapsulated bioactive ingredients into foods can be effectively used to enhance their stability during the processing and storage stage and their bioavailability as well as to delay lipid oxidation and microbial growth in food, without negatively affecting physicochemical, organoleptic and qualitative properties. However, some published results to date declared that food matrix might adversely affect the bioavailability and antimicrobial activity of nanoencapsulated ingredients. It seems that further studies are required to contribute to the choice of appropriate healthy ingredients and wall materials for incorporating into a given food structure.

Effect of different physicochemical de-tartration methods on red grape juice quality.

Grape contains a great deal of tartaric acid and minerals such as Potassium and Calcium which during ripening of grape increase in concentrations and result in potassium and calcium tartrate precipitation in grape juice. There have been different methods introduced for de-tartration but none of them have been completely successful. These methods can be categorized into two different groups of physicochemical and instrumental methods. In this study application of cold treatment, cream of tartar (Potassium bitartrate), Carboxymethyl Cellulose (CMC), and Mannoprotein were investigated. Then all these samples were stored at 5 °C to stimulate tartrate crystals precipitation and were investigated for color indices change, the amount of sediments, acidity, pH and taste. Among these methods addition of Mannoprotein and CMC were proved to have ability in stabilizing tartrate crystals in red grape juice.