fOoD FoR LiFe: ECONOMIC, NUTRITIONAL & MEDICINAL VALUE OF FRUITS & VEGETABLES

INTRODUCTION

Fruits and vegetables are both edible plant products that are good for health. Vegetables are most often consumed as salads or cooked in savory or salty dishes, while culinary fruits are usually sweet and used for desserts, but it is not the universal rule. Some vegetables can be consumed raw, while some, such as cassava, must be cooked to destroy certain natural toxins or microbes in order to be edible.

A number of processed food items available on the market contain vegetable ingredients and can be referred to as "vegetable derived" products. These products may or may not maintain the nutritional integrity of the vegetable used to produce them. Fruits and vegetables contain certain economic, nutritional and medicinal values in their constituents. So, the maintenance of the integrity of those values in processed food is important.

ECONOMIC VALUES OF FRUITS AND VEGETABLES

Since the 1980s, international trade of fruit and vegetables has been characterized by tremendous growth, driven by rising incomes and the expansion of the middle class worldwide (http://www.cggc.duke.edu/). At the beginning of the 21st century, the global industry accounted for US$56.1 billion, and by 2008, exports reached more than twice that value at US$139.6 billion (UNComtrade, 2011).

This export industry offers an important source of employment for developing countries. Cultivation of fruit and vegetables is substantially more labor-intensive than growing traditional cereal crops and offers more post-harvest opportunities to add value.

The rapidly expanding global business of the fruit and vegetables industry has had important consequences for production systems in developing countries. In the past, individual farmers determined varieties grown, quality levels, and production processes employed, and traders bought the product at the farm gate or from wholesalers. Today, the horticulture industry is increasingly organized by long-term relationships and closer linkages between a range of different-sized producer and exporter firms.

Historical production patterns notwithstanding, there is still growing demand for locally grown fresh fruits and vegetables. It has the economic impact potential of local foods production, and the dimensions of value added activity that may serve to boost local economies – both on a small, community scale as well as a regional level.

Fruits and vegetables are heavy, perishable freight, so it must assume that distance and time matter, and producers will focus primarily on serving nearer markets rather than more distant sales venues. The effects of distance on transport costs, these values represent the total costs of operation as well increase the price of the final product which can be affect the consumer preferences.

There are combined fruit and vegetable establishments that had employees on payroll. They are the fruit and vegetable markets to emulate the average national characteristics of these types of operations, considering average sales per operation nationally, and assuming farmers sold half of their production directly to retail customers and the remainder to existing wholesalers, many establishments would be required. It is obvious that the capacity does not exist to distribute fruits and vegetables widely on a retail basis if those averages were in fact applied to the region.

The establishments are in operation; it will staff the operations and pay that staff, it will provide estimates of proprietors’ and investors’ incomes as well. In short, the direct values of such an operation will be estimated as if they in fact could exist. In addition, estimates are made of the induced values that would be attributed to those fruit and vegetable retail workers and their owners (the farmers) when converting their labor incomes into household consumption.

A very large fraction of the transportation, processing, and distribution industries already exists in some form or another where they offer efficient distribution of all fruit, vegetable, and other perishable commodities via existing retail grocery establishments. It does not follow that there will be substantial new productivity added to those sectors by developing farmer-retail operations. Additional value-chain needs to be conducted to evaluate the jobs and facilities needed to distribute and sell locally grown fruits and vegetables.

NUTRITIONAL VALUES OF FRUITS AND VEGETABLES

There is a wide range of fruit and vegetables available in Hong Kong. The nutrient contents of the fruit and vegetables vary, and can change significantly after preparation such as boiling, stir-frying and peeling.

Nutrition is one of the major lifestyle risk factors related to development of non communicable diseases (NCDs). Unhealthy diets, together with physical inactivity, are among the leading causes of NCDs, including cardiovascular disease and certain types of cancer. Fruit and vegetables are important components of a healthy diet. Accumulating evidence suggests that they could help prevent major diseases such as cardiovascular diseases and certain cancers principally of the digestive system.

WHO recommended individuals to consume 400g or more fruit and vegetables per day to protect against obesity and cardiovascular diseases. One of the functional components of fruit and vegetables is dietary fibre. WHO recommended a population intake goal of 25g per day for dietary fibre to substantially reduce the risks of many chronic diseases.

Fruits

Dietary fibre : Fruit is an important source of dietary fibre in our diet. The dietary fibre content of 100g fruit in the list ranged from 0.4g to 6.7g, with a mean of 2.3g. Avocado, guavas, durian, kiwi fruit and western pear were fruits with highest fibre content.

Vitamin C : Fruit is an important source of vitamin C. The vitamin C content of 100g fruit and vegetables in the list ranged from 2mg to 228.3mg, with a mean of 39 mg. Guava, black currant, kiwi fruit, longan, and lychee are fruits rich in vitamin C.

Energy : Fruits are generally regarded as low-energy food. The mean energy value of fruits is 60 kcal per 100g. Fruit high in fat or sugar usually have higher energy value. Although most fruits are low in fat, avocado and durian are two of the exceptions. 100g of avocado and durian contains 14.66g and 5.33g of fat respectively. The energy values of the fruits are also high, that is, 160 kcal per 100g avocado and 147 kcal per 100g durian.

Sugar content is generally higher in fruit than vegetables. Lychee, mango and grapes are examples of fruit with high sugar content. Canned fruits have higher sugar levels than fresh fruits. The energy values of these high-sugar fruit were found to be generally higher than other fruit.

Vegetables

Dietary fibre : Similar to fruit, vegetables are also an important source of dietary fibre in diet. The dietary fibre content of 100g vegetables in the list ranged from 0.5g to 4.9g, with a mean of 1.9g. Lotus root, garland chrysanthemum, Chinese chives (flower stalks), carrot and broccoli were found to have higher dietary fibre content.

Vitamin C : Vegetables are a good source of vitamin C. The vitamin C content of 100g vegetables ranged from 1.4mg to 120mg, with a mean of 26mg. Bitter cucumber, broccoli, mustard leaf, Chinese kale and pea shoots have the highest vitamin C content among vegetables.

Energy : Similar to fruit, vegetables have low energy value. The energy value of vegetables ranged from 8.4 kcal to 74 kcal per 100g, with a mean of only 26 kcal per 100g. However, the energy value of vegetables could greatly increase when fat and oil was added in the process of cooking and seasoning.

Nutritional value of fruits and vegetables

MEDICINAL VALUES OF FRUITS AND VEGETABLES

Food is essential to human life because it is the source of energy and nutrients. Eating the right amount of different kinds of food is the key to a balanced diet and optimal nutrition. Many chronic diseases such as coronary heart disease, diabetes and certain types of cancer are related to imbalanced diet. Fruit and vegetables provide essential vitamins and minerals, dietary fibre, and other substances that are important for maintenance of good health.

WHO recommended a population intake goal of 25g per day for dietary fibre to substantially reduce the risks of many chronic diseases.3 Besides, a set of population nutrient intakes was proposed by the WHO and Food and Agriculture Organization of the United Nations (FAO) as a part of recommendation for prevention of chronic diseases.

The medicinal value is subordinated to the nutraceutical value and some foodstuffs may have medicinal qualities, one of the possible functions of a foodstuff being the therapeutic one. The entire group of the Alliaceae vegetables (garlic, onion, parsnip, etc) contains organic compounds with sulphur that intensify the redox cycle of glutathione and activate specific immunity types. Their bioactivity includes an antioxidant, antibacterial, anti-carcinogenic, immune stimulating and liver protective potential. Garlic prevents heart diseases (atherosclerosis, hypercholesterolemia and high blood pressure) and caner. Garlic is also considered an efficient remedy against the intestinal parasites.

Thyme is a selective disinfectant, irreplaceable in the intestinal infections. The large diversity of species of cabbage, broccoli, heads of cabbage (white, red and savoy), cauliflower of all colors and the Brussels sprout have an anti-radical activity proven by their remarkable contents in polyphenols, flavones and condensed tannins.

The anthocyanic pigments from the black grapes (and from many red/violet fruits) are used in the prophylaxis of many diseases, where the free radicals are involved for ameliorating the flexibility and reducing the permeability of capillaries for retina protection (the ocular vascularity). Flavonoids are the bioactive substances from citric fruits, tea and wine that have an anti-inflammatory activity fortifying the human body against allergies, viruses and the factors inducing tumours.

The health problems, related to the digestive system, such as constipation, or the nutrition ones, such as obesity, may be solved only by an adequate nutrition based on fruits and vegetables. The accelerated aging, the cardio-vascular and degenerative diseases, many types of cancer (pulmonary, colon, stomach, prostate, breasts, etc.) may be prevented due to the antioxidant effect of carotenoids (β carotene, lycopene, etc), tocopherols, L-ascorbic acid, polyphenols, capsaicin, resveratrol and other constituents from the horticultural products. These also contain volatile oils, phytoncides, sulphur glycosides, etc.

The additional treatments based on the cure of grapes, apples, blackberries, black currants, broccoli, carrots, etc. They know vegetables and fruits with diuretic, hypoglycaemic, hypotensive, antiatherosclerotic effects that act against kidney diseases or stomach ulcers.

Species	Main dietic, medicinal features
Carrots	Digestive, hepatic, diuretic, vitaminizing, anti-anaemic, depurative, detoxifying and emollient effect; dietetic product for children, sick people or workers in the toxic/radioactive environment
Early radishes	Vitaminizing, re-mineralizing effect; early vegetables
Radishes	Vitaminizing, re-mineralizing effect; anti-lithiasis, hepatic, pectoral product. It must be consumed all the year round
Beet	Re-mineralizing, general tonic, antibacterial, depurative, diuretic effect
Root of celery	Stimulating, general tonic, diuretic, glycaemia reducer effect; winter consumption
Root of parsley	Diuretic, tonic-stomachic, stimulating, anti-anaemic, vitaminizing, revitalizing, detoxifying effect; aromatizing stuff used in the canned food industry and gastronomy
Parsnip	Tonic, stomachic, depurative, detoxifying effect