This paper assesses critically the science base that underpins the argument that oxidative damage is a significant causative factor in the development of human diseases and that antioxidants are capable of preventing or ameliorating these disease processes. The assessment has been carried out under a number of headings, and some recommendations for future research are made based on the present day knowledge base. The knowledge database (1) Consideration of the basic science that underlies understanding of the role of free radicals in causing cellular pathologies, and the role of antioxidants in preventing this, shows that an imbalance of reactive oxygen species and antioxidant defence systems may lead to chemical modifications of biologically relevant macromolecules. This imbalance provides a logical pathobiochemical mechanism for the initiation and development of several disease states. Experimental data obtained in vivo provide evidence that antioxidants function in systems that scavenge reactive oxygen species and that these are relevant to what occurs in vivo. The relevance in vivo of these observations depends inter alia on knowledge of the uptake and distribution of the antioxidant within the human body, and on what tissue levels of the antioxidant may be expected in relation to dietary levels. (2) There is some way to go until validated precise methods are available for measuring biomarkers of oxidative damage in human subjects in vivo under minimally invasive conditions. With respect to oxidative damage in DNa, HPLC and GC-mass spectrophotometry methods have both merits and limitations. Lipid oxidation products in plasma are best measured as isoprostanes or as lipid hydroperoxides using specific HPLC techniques. Development of isoprostane measurement will advance specificity and precision. The measurement of oxidative damage to proteins has some potential but such methods have not been effectively exploited. (3) Epidemiological studies support the hypothesis that the major antioxidant nutrients vitamin E and vitamin C, and beta-carotene (which may or may not be acting as an antioxidant in vivo), may play a beneficial role in prevention of several chronic disorders. More research is needed on the impact of other non-nutrient compounds, such as other carotenoids and flavonoids, on human health. In general, human intervention studies using hard end-points are the gold standard. Trials are restricted mainly to the major antioxidants and do not allow firm conclusions because of inconsistent findings, an insufficient number of studies and the use of varying doses. There is evidence that large doses of beta-carotene may be deleterious to the health of certain subgroups of the population such as heavy habitual smokers. (4) With respect to the safety of administration of supplementary vitamins, vitamin C is safe at levels of supplementation up to 600 mg/d, and higher levels, up to 2000 mg/d, are without risk. Vitamin E has a very low human toxicity and an intake of 1000 mg/d is without risk; 3200 mg/d has been shown to be without any consistent risk. Large intakes of beta-carotene must be viewed with caution because they have been shown to confer detriment to a population at high risk of lung cancer when administered after many years of high risk (smoking) behaviour. Until further work clarifies the situation in heavy smokers with respect to taking supplements, larger doses should be avoided by such individuals. There is little reliable information about the human toxicology of flavonoids and related non-nutrient antioxidant constituents of the diet. (5) The food industry has long experience in the control of oxidative damage in foods and this experience can be used to advantage for the protection of food antioxidants which are beneficial. Some of these, such as vitamins C and E and beta-carotene, are well known, and strategies for their protection in foods are already exploited by food technologies. (ABSTRACT TRUNCATED)

/pdf/functional-food-science-and-defence-against-reactive-84rpfoebh4.pdf

Functional food science and defence against reactive oxidative species.

Carrot is one of the important root vegetables rich in bioactive compounds like carotenoids and dietary fibers with appreciable levels of several other functional components having significant health-promoting properties. The consumption of carrot and its products is increasing steadily due to its recognition as an important source of natural antioxidants having anticancer activity. Apart from carrot roots being traditionally used in salad and preparation of curries in India, these could commercially be converted into nutritionally rich processed products like juice, concentrate, dried powder, canned, preserve, candy, pickle, and gazrailla. Carrot pomace containing about 50% of β-carotene could profitably be utilized for the supplementation of products like cake, bread, biscuits and preparation of several types of functional products. The present review highlights the nutritional composition, health promoting phytonutrients, functional properties, products development and by-products utilization of carrot and carrot pomace along with their potential application.

/pdf/chemical-composition-functional-properties-and-processing-of-7ixwkyyf1h.pdf

Chemical composition, functional properties and processing of carrot—a review

Effect of thermal and non thermal processing technologies on the bioactive content of exotic fruits and their products: Review of recent advances

Drying of food consists of three steps, namely pre-drying processing, dehydration and post-drying handling of the material. The pre-drying processes depend on the physical state of the material subjected to drying. Liquids are vacuum concentrated, treated with enzymes or foamed, while solids are sulfited, soaked in solutions of different compounds, dewatered by osmosis, blanched, frozen or treated by high pressure. Drying of the pre-treated material can be done under vacuum or at atmospheric pressure. Material undergoing drying can be heated by surface heating or by volumetric heating, and it can be stationary or set in motion. Storage stability of a dry material depends on the state at which the drying process is finished. The effect of all these steps on quality of the final product are discussed. It is shown that to design a process of hot air drying a thorough understanding of all the operations affecting quality is needed.

Design of hot air drying for better foods

Biodegradable Soy Protein Isolate-Based Materials: A Review

Carotenoid and anthocyanin contents of papaya and pineapple: Influence of blanching and predrying treatments

The effect of various pHs on winged bean and soybean protein-lipid films formation, proximate composition and rehydration capacity were studied. Film can only form within a specific range of pH. Films prepared at high pHs (7.5, 9.0, 10.0 and 11.0) contained higher proportions of proteins, ash and carbohydrate but lower proportion of fat than those at pH 6.7, 2.5 and 2.0. Winged bean and soybean films were found to have different pattern of rehydration, however both tended to absorb more water at high pH. With regard to film formation efficiency, nutritional value (higher protein content) and rehydration capacity, soybean film is better than winged bean film.

Ng Kok Sian

Papers

Carotenoid and anthocyanin contents of papaya and pineapple: Influence of blanching and predrying treatments

Effect of pH on Formation, Proximate Composition and Rehydration Capacity of Winged Bean and Soybean Protein‐Lipid Film