Sale of cut fruits through push carts near many schools across the country is a common sight and many parents try to prevent their children from patronizing such road side vendors fearing its potential for diseases like diarrhea caused by microbial contamination. Many schools restrict the operation of such vendors near their premises though without much success. Lately such vendors seem to be spreading in many urban areas offering cut fruits from Papaya, Guava, Water Melon, Pineapple, Jack fruits, Green mango etc during the fruit seasons. Generally the cut fruits are laced with a mixture of salt and chilli powder to make them tastier. Fruit chat preparations popular in northern parts of India use black salt on cut fruits including banana, sapota, apple and other seasonal fruits. In all these cases the cut fruits are prepared on the spot in front of the consumer and are not kept for more than a few minutes that ensures minimum microbial contamination. However the personal hygiene of the vendor, cleanliness of the utensils and knives used, safety of the plates in which it is served are all risks one has to take when patronizing such road side preparations in India.
The dangers inherent in road side vending is too well known to be discussed and the clientele consists of mostly school children near the teaching institutions and lower middle class population having good immunity to infections commonly encountered in public place eating. If a more decent and better product is available with assured safety, the clientele can be expanded and sky is the limit for developing this line of business. True, hotels and restaurants do serve fruit salads based on seasonal fruits, but it is unlikely any one will visit such joints only for fruit preparations and generally they are part of the meal, being a dessert preparation. Besides the very concept of a fruit preparation, being all natural and healthy, is compromised by serving them with ice cream or custard. In such a situation products like fresh cut fruits with longer shelf life and easy delivery mode, can fill a vacuum in the market and provide incentives to the consumer to eat fruits more regularly to meet with the recommended dietary guidelines for consuming 4-6 servings of fruits and vegetables daily by normal healthy persons.
Fruits are biologically respiring and transpiring materials taking in oxygen and giving out CO2 and water at ambient temperatures. Even as a whole fruit, its life is limited and its quality can slide down rapidly losing its characteristic texture and flavor with time. Cold stores with appropriate low temperature conditions and controlled atmosphere storage technology can extend the life by a few days though there is a limit for its ultimate life. Some fruits like mango have very short life while others like apple stay well for months together under ideal conditions. When fruits are cut, the quality deteriorates rapidly due to release of destructive enzymes which can impart discoloration, textural changes and off flavor if not properly processed. Poly Phenol Oxidase (PPO) is the most destructive enzyme which produces ortho quinones on the cut surface, a highly reactive substance capable of further reaction non-enzymatically with other quinones, phenolic compounds, thiol compounds, proteins, peptides and amino acids etc to produce brown, blue-grayish and black colors on the cut surface.
Fruits after cleaning, peeling and removal of inedible parts are cut into cubes or chunks of desired size, washed well, spin dried to remove adhering water and shrink wrapped for display and retailing under low temperature conditions, 4-8C with a limited life of 2 days beyond which they cannot be sold. These preparation steps and cutting introduce a series of physiological disorders like softening, browning and microbial infection, all considered undesirable from consumer perspectives. To prevent or lessen the undesirable changes, treatments with ascorbic acid (Vit C), its isomer erythorbic acid, edible organic acids, sodium phosphate, sulfites etc are resorted to by the processors. Though sulfiting is one of the most effective pretreatment procedures practiced by the industry, severe allergy to SO2 by many consumers makes this less and less acceptable as a universal practice. As freshly cut fruits are physiologically still active, the tissues being alive and respiring all the time and requires about 2% oxygen in the atmosphere surrounding them. Use of sodium alginate, gellan gum, modified starch, pectic substances, carrageenans etc as a coating reduces surface enzyme and non-enzymatic activities significantly. pH being less than 3 on the cut surface also helps slowing down the enzymatic reactions. Infusion of O2 containing gas mixture maintains the Kreb's Cycle biochemical reactions generating CO2 which protects the fruit surface from microbial spoilage.
It is intriguing as to why the coin operated vending machines widely used for dispensing products like soft drinks, chocolate candies, snacks etc are not adopted for cut fruit vending also. The technology of extending the life of cut fruits to 7-30 days is readily available for the industry to introduce such vending system in a massive way and popularize its consumption especially amongst the youngsters. The Singapore experience where vending machines are being tried in a limited way to dispense chilled and diced fruit chunks under refrigerated conditions at an affordable price of S$ 1-1.8 per cup, transparent and sealed, has already shown the business viability of such an approach. Each vending machine with a capacity to store 180 cups can be left unattended for two days unless refilling is called for, since the products have at least 5 days life once loaded into the machine. It should be possible to design larger capacity machines, if the response and demand increase for the products amongst the consumers. It is time such retailing format is thought of in India also where a fantastic range of fruits are available all around the year.