Should we cook vegetables, or eat them raw? Vegetables house their constituents in a rigid cell wall known as cellulose, or fiber. Unfortuanately, humans do not produce the enzyme, cellulase, to effectively bind to and break down cellulose. Fortunately, we can forego this a bit by thoroughly grinding down our food when chewing, natural fermentation that happens during the digestive processes and relying on a healthy microbiome in our large intestine were the bacteria can break it down into short chain fatty acids which later get metabolized into butyrate, the fuel for our colon. Does that mean we should eat all vegetables raw to maximum nutrition? That may not be the case. As humans, not only do we respond differently to the same foods due to genetic polymorphisms, different foods can change the message expressed by our unique genes. You see, different foods host nutrients and bioactive compounds that are specific to them. For example, cooked tomatoes contain lycopenes that down regulate growth promoting genes in prostate glands. Cooked tomatoes, prostate cancer risk goes up and without, the reverse. Research indicates that certain vegetables will increase their antioxidant activity with certain cooking methods where others may not. Vegetables contain several hydrophilic and lipophilic antioxidant compounds and it is important to estimate the antioxidant activity using different methods. They may act together more effectively than singly because they function synergistically and are capable of quenching free radicals in both aqueous and lipid phases (Ohr 2004; Trombino and others 2004). Antioxidant compounds may also act as metal chelators and interfere with the pathways that regulate cell division and proliferation and detoxification; they also may regulate inflammatory and immune responses, and may have antiulcerative properties (Hamauzu and others 2008). They may inhibit or activate a large variety of mammalian enzyme systems, exhibiting biphasic dose responses in cells at low doses. Phytochemicals activate signaling pathways that result in the increased expression of genes-encoding cytoprotective proteins, including antioxidant enzymes (Dragsted and others 2006), protein growth factors, and mitochondrial proteins. Examples of the phytochemicals: sulphorane or isothiocyanates (present in broccoli) and allicine (present in garlic) (Mattson 2008). Most of common vegetables are consumed after being cooked. Thus, it is important to know what happens to their antioxidant activity or free radical capacity during common domestic processes (boiling, frying, microwave cooking). Because modern day consumers seek to avoid aggressive cooking methods which may affect the functionality of foods, there is growing interest in the phytochemical profiles and antioxidant activities of cooked (boiled, microwaved, steamed, griddled, fried, and baked) vegetables. This article attempts to determine the optimum cooking method that results in the highest retention of the antioxidant capacity and radical scavenging activity of vegetables, to improve their functional activity. Full Text HTML: onlinelibrary.wiley/doi/10.1111/j.1750-3841.2009.01091.x/full
Posted on: Sun, 26 Jan 2014 00:25:54 +0000
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