Introduction
Food processing/preparation methods help preserve the nutritional integrity of food products and enhance the bioavailability of dietary nutrients. The methods also enhance food safety by eliminating food-borne microorganisms that may cause diseases. However, some processing steps affect sensitive nutrients such as vitamins, proteins, and minerals and thus, reduce their bioavailability in the diet (Afoakwa, Budu & Merson 2007). Food canning and blanching are some of the common methods used in food processing.
Food cultivation methods also affect the safety and nutritional value of foods. In particular, evidence from past studies has found significant nutritional differences between food crops grown organically and those cultivated using conventional methods (Lima & Vianello 2011). In particular, organic food products have been found to have higher levels of nutrients like vitamins and phenolic compounds and lesser pesticides and nitrates compared to food produced through conventional farming (Lima & Vianello 2011). This essay will compare, contrast, and evaluate the impact of food processing (canning and blanching) techniques as well as farming methods (organic and conventional farming) on the nutritional value of food crops. It will review relevant literature to provide a deeper insight into the characteristics and effects of these methods on nutrition.
Food Processing Methods
Canning and blanching are feasible food processing techniques of the 21st Century. In blanching, the food crops, usually fruits and vegetables, are subjected to heat treatment using steam, ultrasound, boiling water, or hot air to kill food-borne microorganisms (Rahman & Perera 1999). Blanching procedures “inactivate nutrient-degrading enzymes in food”, and thus, preserve sensitive nutrients, including vitamins, minerals, and flavor in food products (Rahman & Perera 1999, p. 67). The technique also eliminates oxygen from the food making it less prone to food spoilage. On the other hand, canning encompasses various sterilization procedures that eliminate microorganisms on a food product to prolong its shelf life. According to Rafique Iqbal, Faiz, and Hashmi (2009), canning enhances the bioavailability of dietary macronutrients by denaturing amylase and trypsin inhibitors occurring in beans and grains. The sterilization step also inactivates thiamine-degrading enzymes in fish, seafood, and cabbage and therefore, increases the bioavailability of thiamine present in these foods (Rafique et al. 2009).
Although canning and blanching of food increase the bioavailability of nutrients, these procedures destroy the heat-sensitive nutrients leading to nutrient loss. Canning destroys vitamins soluble in water, such as thiamine, as they are more sensitive to heat treatment than fat-soluble ones (Rafique et al. 2009). Afoakwa, Budu, and Merson (2007) note that nutrient loss in canned food depends on the amount of heat that is applied during the pre-treatment step, the type of tin, and the type of nutrients in the food. Blanching has also been associated with nutrient loss. Blanching that uses boiling water causes the leaching of water-soluble nutrients such as vitamin C and thiamine (Ramesh, Wolf, Tevini & Bognar 2002). However, a study by Gamboa-Santos, Montilla, Soria, and Villamie (2012) established that blanching using the ultrasound method inactivates degenerative enzymes, pectin methylesterase, and peroxidase, which reduce the risk of leaching. Thus, the use of techniques such as hot air or ultrasound can reduce nutrient leaching during blanching.
Canned or tinned food is highly popular around the world. Most plant and animal products can be canned, but each food type requires different canning conditions to preserve nutrients and destroy microorganisms that cause food spoilage. In contrast, over the last decade, there has been a growing use of blanching in the preservation of fruits and vegetables, especially carrots due to their immense nutritional benefits (phenols) as well as anticancer and antioxidant properties (Gamboa-Santos et al. 2012). Since blanching involves mild treatment of perishable produce, the technique does not have much effect on the nutritional value of food. Moreover, blanching only denatures peroxidase enzymes that accelerate the degeneration of food (Rahman & Perera 1999). In comparison, in canning, the pre-treatment and canning conditions can lead to nutrient loss. For instance, Rafique et al. (2009) established that the canning of spinach and tomatoes leads to loss of essential micronutrients such as zinc, copper, and nickel through the water in the cans. Thus, overall, blanching is an effective food processing technique compared to food canning.
Farming Methods
Organic food crops differ in terms of nutritional value from food crops grown through conventional farming methods (fertilizer-based). Studies have found differences in micronutrient levels, including minerals and vitamins, between fruits/vegetables grown organically and those cultivated using conventional farming methods. Bourn and Prescott (2002) found that organically grown strawberries, apples, and potatoes, among others, have less nitrogen content, high mineral content (calcium, sodium, and iron), and high levels of vitamin C. In contrast, food crops grown through conventional farming, which involves the use of fertilizers (nitrates) and pesticides, have relatively high nitrate and pesticide levels (Lima & Vianello 2011). Thus, the type of fertilizer used can cause variation in nutrient content between these food types.
Organic farming relies on manure-based fertilization, while conventional farming uses synthetic nitrate fertilizers. Stracke, Rufer, Weibel, Bub, and Watzl (2009) report that manure-based fertilization results in improved vitamin A, C, and B12 compared to nitrate-based fertilization of various crops grown under similar climatic conditions. The difference in fertilization between the two methods causes variations in nutrient content. Another study by Raigon, Rodriguez-Burruezo, and Prohens (2010) found a variation in the level of phytochemicals in food crops grown using the two farming methods. Phytochemicals are phenolic compounds such as lycopene (tomatoes) and carotene (carrots) that protect crops from pests (Stracke et al. 2009). The differences between conventional and organic farming practices affect the level of phenolic compounds in food products. Phenolic compounds influence food flavors as well as the anticancer and antioxidant properties of food. Thus, an evaluation of the nutritional value of organic- and conventional-plant-based food is important as they have significant effects on physical health. The evidence reviewed in this paper indicates that organic farming produces nutritionally superior food compared to conventional farming.
Nutrition and Health
Conditions such as obesity, diabetes, hypertension, and certain cancers have been associated with unhealthy dietary habits (Dangour et al. 2009). Dietary imbalances arise when an individual’s nutrient intake does not reflect his/her RDA requirements. Dietary imbalances increase the risk of developing chronic diseases. Moreover, food products (fruits and vegetables) that have low vitamin and mineral content cause diseases such as anemia (iron deficiency), night blindness (vitamin A), and scurvy (vitamin C), among others. Nutritionally superior food products provide macro-and micro-nutrients in the correct amounts in the diet and thus, reduce the risk of developing chronic diseases.
Conclusion
Food processing and farming methods have significant impacts on the nutritional value of foods. Food processing techniques such as blanching and canning not only cause the loss of micronutrients (vitamins and minerals), but also affect the bioavailability of essential nutrients in the diet. Farming methods, including conventional and organic farming, also alter the nutritional value of food due to the effects of fertilizers and pesticides. The emergence of chronic conditions in the 21st Century warrants the evaluation of existing techniques in order to identify good farming practices and food processing techniques that would improve public health outcomes.
References
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