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Abstract

Free fatty acid content, conjugated dienes content, total phenolic content and turbidity measurements of organically produced natural olive oil samples were 3.43, 1.06, 43.87, 0.17 for the samples of the 2005 season and 0.88, 0.12, 98.58, 26.61 for the samples of the 2008 season, respectively. During storage, levels of the free acidity and conjugated diens of olive oil samples increased while their turbidity value and total phenolic content decreased. As the CIE color values of L and a* increased, b* value decreased during storage. Stored samples had the absorbance maximum between 240 and 270 nm wavelengths. On the other hand, acidity levels in crude olive pomace oil and 2nd extraction oil were very high and reduced to acceptable limits after refining. Contrarily, refining reduced total phenolic content of olive oils significantly. Similarly, refining also reduced turbidity and a* values in the pomace oils. The range for maximum absorbance was wider for pomace oil samples than the virgin olive oils. In addition, absorbance peaks at 415 and 670 nm were absent for virgin olive oil samples. In conclusion, virgin olive oils should not be stored more than 3 years for marketing purposes.

Key Words: Olive oil, Crude olive pomace oil, Conjugated diene, Phenolic content

Abstract

Pesticides are frequently used in modern agriculture to improve production by reducing pest populations. Besides concerns like environmental pollution and destruction of non-target organisms, there are also health concerns due to the pesticide residues on foodstuffs. Studies have shown that the oxidants with high redox potential can be used to minimize or completely eliminate pesticide residues on some of the foods, especially fruits and vegetables. Toxicological evaluation of the degradation products of pesticides could be helpful to minimize health concerns. Recently, studies have been extensively focused on the toxicity of degradation products of pesticides. Ozone, one of the oxidants tested, is a promising agent because of its high residue removal efficiency and spontaneous decomposition without forming any subresidues. Other oxidants used for this purpose include hydrogen peroxide and chlorine. In addition, advanced oxidation processes, combination of ozone, hydrogen peroxide, titanium dioxide and UV, present alternative to oxidants alone for pesticide removal because their combination has high efficiency besides ease of use, and lack of toxic residues. In this paper, the use of various oxidizing agents to remove pesticide residues from foodstuffs was reviewed.

Key Words: Pesticide residue, Residue removal, Oxidant, Advanced oxidation processes, Fenton process

Abstract

The typical aroma of wine is mainly associated with volatile compounds coming from grapes. These compounds are present in grapes and wines as free or bound forms. Aroma compounds in young wines are mostly in their glycosidically bound forms. Aroma compounds such as terpens, norisoprenoids, benzene derivatives and straight chain alcohols can be released by acid or enzymatic hydrolysis. The enzyme group of glucosidases is used for enzymatic hydrolysis of these compounds. The effect of commercial glucosidase preparations produced from various microbial sources on white wine aroma has been investigated in many studies. The results showed that the enzyme preparations with considerable activity of glucosidase could increase the aroma potential of white wine and improve sensory attributes of wines. Appropriate purification and immobilization procedures must be applied to increase the activity and stability of glucosidases.

Key Words: White wine, Glucosidase, β-Glucosidase, Aroma

Abstract

Carotenoids, which can not be synthesized by mammals, are fat-soluble antioxidant pigments. Antioxidant and vitamin A activity of carotenoids are the most important functions depending on consumption and absorption, transport, metabolic reactions in the body and the storage introduce functional benefits on visual, cancer and heart diseases. Carotenoid bioavailability is defined as the ratio of absorbed and used carotenoids in the body. Factors affecting the bioavailability of carotenoids are the physical and biochemical characteristics of carotenoids, metabolic reactions, carotenoid types and isomers, various food processes that affect food matrix, dietary factors including fiber and fat, aging, hormonal and genetic factors. This study focused on the structure and stability of carotenoids, methods used to determine bioavailability of carotenoids and the factors affecting bioavailability.

Key Words: Carotenoids, Bioavailability, Digestion, Absorption

Abstract

The use of microwave applications in food industry has increased dramatically over the past few decades. Microwave heating of any material is based on so called dielectric heating, in which energy is absorbed by ions or molecules that are either induced or permanent dipoles. Upon exposure to the microwave field, polar molecules and ions align themselves by the rapidly changing direction of the field, during which heat is generated throughout the material. The most important characteristic of microwave heating is volumetric heating. In this study, the fundamentals of microwave technology and microwave assisted-vacuum drying method for foodstuffs are reviewed.

Key Words: Drying, Microwave, Microwave assisted vacuum drying

Abstract

Food safety and quality are the main criteria for food industry. In the recent years, the objective measurement of food product properties related with shape and color has been achieved by computer vision technology. In this paper, innovative computer vision technology developed for quality control of various foods was reviewed.

Key words: Computer vision, Food, Quality control.