Maximizing the Nutritional Value of Fruits and Vegetables

1 BY Diane M. Barrett Maximizing the Nutritional Value of Fruits & Vegetables Review of literature on Nutritional Value of produce compares fresh, frozen, and canned products and indicates areas for further research. I. nterest in the Nutritional Value thiamin, riboflavin, B-6, niacin, of providing the recommended 5 . of Fruits and Vegetables has been folate, A, and E. Phytochemicals 13 daily servings year round. In the increasing, in part because of in Fruits and Vegetables , such as , Fruits and Vegetables grown recent findings on the high level polyphenolics, carotenoids, and in North America may spend up to of obesity and other diet-related glucosinolates, may also have 5 days in transit following harvest health problems in children and in Nutritional Value . While many before arriving at a distribution part because of increased federal Fruits and Vegetables are consumed center.

2 Transportation time for support of programs funding primarily in their fresh state, some Fruits and Vegetables grown in the consumption of fresh and processed produce such as tomatoes, snap southern hemisphere for winter fruit and vegetable products. beans, corn, peaches, nectarines, and spring consumption in the The following discussion and pineapples are also consumed ranges from as little as a few is based in part on a review by to a significant degree in their days if transported by air freight to Rickman et al. (2007a, b) of recent processed state. Table 1 lists per- several weeks if sent by refrigerated literature on the Nutritional Value capita consumption of selected ship. At the retail store, Fruits and Fresh Fruits and Vegetables may not be consumed for a significant length of time following harvest, during which time nutrient degradation may occur.

3 Of fresh, canned, and frozen Fruits fresh, frozen, and canned Fruits Vegetables may spend 1 3 days on and Vegetables . The review was and Vegetables in the United States display prior to being purchased commissioned by the Canned Food (ERS, 2004). by the consumer, who may store Alliance and prepared by faculty of Fruits and Vegetables are often them for up to 7 days prior to the University of California Center the most attractive and health- consumption. This means that for Excellence in Fruit & Vegetable promoting when harvested at their fresh Fruits and Vegetables may Quality (see sidebar). peak maturity, but most Americans not be consumed for a significant do not have home gardens capable length of time following harvest, Fresh Fruits and Vegetables during which time nutrient Fruits and Vegetables are a major degradation may occur.

4 Source of macronutrients such as Most Fruits and Vegetables fiber and micronutrients such as are composed of 70 90%. minerals and vitamins C, water and once separated pg 40 Centers Address Fruit from their source of nutrients if Fruits and Vegetables are gently (tree, plant, or vine) undergo handled and stored at high relative and Vegetable Quality higher rates of respiration, humidity and refrigerated. Some C. resulting in moisture loss, quality commodities, such as apples alifornia is the primary producer of and nutrient degradation, and and pears, are stored for up to Fruits and Vegetables in the United potential microbial spoilage. 12 months under controlled- States, and in January 2006, the Uni- In some instances, Fruits and atmosphere conditions that utilize versity of California established a Center Vegetables may be harvested low oxygen and high carbon for Excellence in Fruit & Vegetable Quality immature to reduce mechanical dioxide levels to slow down within the Robert Mondavi Institute of damage during harvesting and respiration.

5 Most perishable Wine & Food Science (http://robertmonda- transportation. Because intact commodities, however, are stored ). Fruits and Vegetables are still alive under refrigerated conditions, and More than 30 scientists ranging and respiring, temperature and storage life may range from 8 10 from economists to consumer scientists, relative humidity must be carefully days for highly perishable Fruits sensory scientists, molecular biologists, controlled to maintain low rates of like berries to 8 10 weeks for chemists, biochemists, postharvest respiration, prevent moisture loss, less-perishable commodities like physiologists, nutritionists, and process and maintain eating quality. squash, pumpkin, apples, grapes, engineers are involved in the Center, Changes in nutrient and pears. which will form an integral part of a new composition from harvest Foods for Health Initiative.

6 To consumption depend to a Processed Fruits and Vegetables The long-term goal is to develop and certain degree on the particular Many Fruits and Vegetables only promote science-based information and nutrient, the commodity, and the grow in specific regions of the technology that increases consumption of postharvest handling, storage, world, in a particular type of Fruits and Vegetables by enhancing both and home cooking conditions. In soil, under certain temperature eating quality and health. To accomplish addition, initial nutrient content and humidity environments, and this, the scientists will focus on three is affected by the particular at limited times of year, and in short- to medium-term objectives: define cultivar ( , Red Delicious and many countries refrigeration is desirable sensory parameters that Fuji apples), soil type, production not available.

7 Processing allows describe consumer perception of fruit system (conventional, organic, Fruits and Vegetables produced and vegetable quality; correlate sensory etc.), and weather conditions in remote regions of the world, parameters with objective measurements (temperature, humidity , daylight such as coconuts, durian, mango, of quality (color, texture, flavor, and hours, etc.) during growth. and papaya, to be stabilized and Nutritional quality); and identify optimal Fruits and Vegetables for transported to distant locations for genetic, preharvest, postharvest, and the fresh market are generally consumption. In many instances, processing practices that maximize harvested by hand, with the Fruits and Vegetables such as quality and Nutritional Value of Fruits and exception of roots and tubers, pumpkin, clingstone peaches, and Vegetables .

8 While many commodities destined some leafy greens and squashes may Other interdisciplinary centers for processing are mechanically be too tough or bitter to consume focusing on foods for health are being harvested. Mechanical harvesting developed at many other universities in generally causes more stress the United States, Canada, Europe, and to the plant tissue and may the rest of the world, including Texas A&M. result in more damage than University, Iowa State University, the hand harvesting. Nutrient University of Illinois, Purdue University, retention is and the University of Minnesota. There is a optimized need to encourage collaboration between scientists at these various universities and identify strengths specific to individual programs which need not be duplicated at other locations. 41 pg Table 1. Per-capita consumption of Fruits and Vegetables in 2004.

9 From ERS (2006). a growing number of researchers Amount (lb) are investigating antioxidant effects Commodity Fresh Frozen Canned using human, animal, or cell-line Asparagus models rather than relying merely Beans, snap on instrumental determination Carrots of model systems that may or not Corn simulate what happens in the body. Green peas Mushrooms Fresh vs Canned and Frozen Peaches and nectarines Vitamin C is water soluble and Pineapple sensitive to heat, light, and oxygen, Spinach making it susceptible to loss Tomatoes during both home cooking of fresh Total for all processing varieties. a Fruits and Vegetables and thermal processing. For that reason, loss of vitamin C is often used as an index unless they undergo thermal nutrients such as vitamins C of nutrient degradation. treatment, either during home and B and the polyphenolics Research indicates that as long cooking or, in the case where the are degraded by processing as fresh products undergo minimal growing location is distant, during treatments and may be leached storage and are handled at proper the canning process.

10 Canning, into cooking water or the canning temperatures, they are superior freezing, dehydration, pickling, medium. Fat-soluble nutrients to processed products in terms fermentation, and other methods such as vitamins A and E and the of vitamin C content. However, of preservation are carried out with carotenoids may be released from vitamin C degrades rapidly after the goal of delivering processed their cellular matrices by thermal, harvest, and this degradation products that are safe and retain freezing, high-pressure, or other continues during storage. Vitamin desirable quality attributes similar preservation treatments. Because C losses in Vegetables stored at to those of fresh products. they have been extracted to a 4 C for 7 days range from 15% for Processing, however, changes greater degree by the treatment, green peas to 77% for green beans.