‡ This paper consists of two parts, the 1st is concerned

1. Minimally Processed Fruits and Vegetables‡Ali Kamil Yousif AlsaedProfessor of Fruit and Vegetable ProcessingDepartment of Nutrition and Food technologyFaculty of AgricultureUniversity of JordanAmman, Jordane-mail akamil@ju.edu.jo

2. ‡ This paper consists of two parts, the 1st is concerned • with a literature review about minimally processed fruits • and vegetables and were extracted from several papers • and mainly from the article given by the Vegetable • Research &Information Center of the University of • California whereas the second part deals with the • Jordanian practice regarding the minimally processed • fruits and vegetables.

3. 1. Review • I. Introduction and definition • *Minimal processing of fruits and vegetables is a state-of-the-art technology by which a variety of tropical, sub-tropical, and temperate fruits and vegetables can be made available in trimmed and cut forms prepackaged with fresh/fresh-like sensory attributes. *Producing minimally processed products involves cleaning, washing, trimming, coring, slicing, shredding, and so on.

4. *Other terms used to refer to minimally processed products are "lightly processed," "partially processed," "fresh- processed," and "pre- prepared." • *Minimally processed fruits and vegetables include peeled and sliced potatoes; shredded lettuce and cabbage; washed and trimmed spinach; chilled peach, mango, melon, and other fruit slices; vegetable snacks, such as carrot and celery sticks, and cauliflower and broccoli florets; packaged mixed salads; cleaned and diced onions; peeled and cored pineapple; shelled peas; peeled citrus fruits; and microwaveable fresh vegetable trays.

5. *The fresh-cut fruit and vegetable industry was first developed to supply hotels, restaurants, catering services, and other institutions. More recently, it has expanded to include food retailers, in response to consumer's demand for fresh, healthy and convenient foods.  • *Due to processing operations, that alter the physical integrity of these products, they are more perishable than the original raw materials. Accordingly, the need for increased sanitation, preparation and handling of these products require knowledge of food science and technology and postharvest physiology.

6. *Minimum processing protocols are generally without thermal treatments, excepting French beans which requires very short thermal treatment. This additives-based non- thermal process is helpful in retaining the freshness of the produce to a longer period. *Minimum processing protocols are generally without thermal treatments, excepting French beans which requires very short thermal treatment. This additives-based non- thermal process is helpful in retaining the freshness of the produce to a longer period.

7. *The minimally processed fruits and vegetables are microbiologically safe, besides being rich in ascorbic acid.*The process condition and additive treatments vary depending on the nature of commodities, viz. whether they are of white flesh, non-green or green colour. *The minimally processed products exhibit a shelf-life of 14-28 days under room temperature (6 ± 1 C).

8. *Growth in demand has led to increased marketing of fresh horticultural products in lightly processed form. An industry dedicated to this type of food processing has been established, and the American National Association of Fresh Produce Processors was recently formed.

9. II. Physiological Responses*Minimal processing generally increases the rates of metabolic processes that cause deterioration of fresh products. The physical damage or wounding caused by preparation increases respiration and ethylene production within minutes, and associated increases occur in rates of other biochemical reactions responsible for changes in color (including browning), flavor, texture, and nutritional quality (such as vitamin loss).

10. *The greater the degree of processing, the greater the wounding response. Control of the wound response is the key to providing a processed product of good quality. *The impact of bruising and wounding can be reduced by cooling the product before processing. Strict temperature control after processing is also critical in reducing wound-induced metabolic activity, as shown in the respiration data of intact and shredded cabbage stored at different temperatures.

11. *Other techniques that substantially reduce damage include use of sharp knives, maintenance of stringent sanitary conditions, and efficient washing and drying (removal of surface moisture) of the cut product. • III. Microbiological Concerns • *Intact fruits and vegetables are safe to eat partly because the surface peel is an effective physical and chemical barrier to most microorganisms. In addition, if the peel is damaged, the acidity of the pulp prevents the growth of organisms, other than the acid tolerant fungi and bacteria that are the spoilage organisms usually associated with decay.

12. *The normal spoilage flora, including the bacteria Erwinia and Pseudomonas, usually have a competitive advantage over other organisms that could potentially be harmful to humans. *The risk of pathogenic bacteria may increase with film packaging (high relative humidity and low oxygen conditions), with packaging of products of low salt content and high cellular pH and with storage of packaged products at too high temperatures (>5°C or 41°F). Food pathogens such as Clostridium, Yersinia, and Listeria can potentially develop on minimally processed fruits and vegetables under such condition

13. *With minimally processed products, the increase in cut/damaged surfaces and availability of cell nutrients provides conditions that increase the numbers and types of microbes that develop. Furthermore the increased handling of the products provides greater opportunity for contamination by pathogenic organisms. *Microbial growth on minimally processed products is controlled principally by good sanitation and temperature management. Sanitation of all equipment and use of chlorinated water are standard approaches. Low temperature during and after processing generally retards microbial growth but may select for psychrotrophic organisms such as Pseudomonas.

14. *Moisture increases microbial growth, therefore removal of wash and cleaning water by centrifugation or other methods is critical. Low humidity reduces bacterial growth, although it also leads to drying (wilting and shriveling) of the product. Low oxygen and elevated carbon dioxide levels, often in conjunction with carbon monoxide, retard microbial growth. • *Plastic film packaging materials modify the humidity and atmosphere composition surrounding processed products and therefore may modify the microbial profile.

15. IV. Product preparation*Minimal processing may occur in a "direct chain" of preparation and handling in which the product is processed, distributed, and then marketed or utilized. Many products are also handled in an "interrupted chain" in which the product may be stored before or after processing or may be processed to different degrees at different locations. Because of this variation in time and point of processing, it would be useful to be able to evaluate the quality of the raw material and predict the shelf life of the processed product.

16. *Minimally processed products may be prepared at the source of production or at regional and local processors. Whether a product may be processed at source or locally depends on the perishability of the processed form relative to the intact form, and on the quality required for the designated use of the product. Processing has shifted from destination (local) to source processors as improvements in equipment, modified atmosphere packaging, and temperature management have become available.

17. *Minimally processed products may be prepared at the source of production or at regional and local processors. Whether a product may be processed at source or locally depends on the perishability of the processed form relative to the intact form, and on the quality required for the designated use of the product. Processing has shifted from destination (local) to source processors as improvements in equipment, modified atmosphere packaging, and temperature management have become available.

18. *Washing the cut product removes sugar and other nutrients at the cut surfaces that favor microbial growth and tissue discoloration. Because of differences in composition and release of nutrients with processing, some products such as cabbage are known as "dirty" products. It is desirable to maintain separate processing lines, or thoroughly clean the line before another product follows cabbage. Free moisture must be completely removed after washing. Centrifugation is generally used, although vibration screens and air blasts can also be used. The process should remove at least the same amount of moisture that the product retained during processing. It has been shown that removal of slightly more moisture (i.e., slight desiccation of the product) favors longer post-processing life.

19. V. Packaging, Modified Atmospheres, and Handling*Polyvinylchloride (PVC), used primarily for over-wrapping, and polypropylene (PP) and polyethylene (PE), used for bags, are the films most widely used for packaging minimally processed products. Multilayered films, often with ethylene vinyl acetate (EVA), can be manufactured with differing gas transmission rates. For lettuce processed at source, a 2.5 mil 8 percent EVA co-extruded PE bag has been used. *Products are often packaged under partial vacuum or after flushing with different mixtures of gases (oxygen, carbon dioxide, carbon monoxide, and/or nitrogen).

20. *Vacuum packaging and gas flushing establish the modified atmosphere quickly and increase the shelf life and quality of processed products. For example, browning of cut lettuce occurs, before a beneficial atmosphere is established by the product's respiration. • *For other products, such as fast respiring broccoli florets, impermeable barrier films are used with permeable membrane "patches" to modify the atmosphere through the product's respiration. It is not yet agreed what are the ideal films and atmospheres for minimally processed products.

21. *In addition to different atmosphere requirements for different products, the specifics of the handling chains must be taken into account, especially their time delays and temperature fluctuations. • *The modified atmospheres that best maintain the quality and storage life of minimally processed products have an oxygen range of 2 to 8 percent and carbon dioxide concentrations of 5 to 15 percent.

22. *Carbon monoxide concentrations of 5 to 10 percent under low oxygen (<5 percent) conditions retard browning and reduce microbial growth, lengthening shelf life in lettuce and other products. • *With some non permeable barrier-type PE films, an elevated oxygen level (25 to 50 percent) is used with carbon monoxide (3 to 10 percent) to maintain aerobic respiration during the handling • period.

23. *The following factors are known to be critical to maintaining • quality and shelf life in minimally processed products: using • the highest quality raw product, reducing mechanical damage • before processing, reducing piece size by tearing or by slicing • with sharp knives, rinsing cut surfaces to remove released • cellular nutrients and kill microorganisms, centrifugation to the • point of complete water removal or even slight desiccation, • packaging under a slight vacuum with some addition of CO to • retard discoloration, and maintaining product temperature at 1° • to 2°C (34° to 36°F) during storage and handling. Temperature • maintenance is currently recognized as the most deficient • factor.

24. *Other techniques such as irradiation, chemical preservation (dips in ascorbic acid, calcium chloride, and/or citric acid), modification of pH, and reduction of water activity (with sugars/salts) may also control deterioration of processed products, mainly by controlling microbial growth. • VI.Quality of Minimally Processed Products • *The nature of the demand for minimally processed products requires that they be visually acceptable and appealing. The products must have a fresh appearance, be of consistent quality throughout the package, and be reasonably free of defects. Field defects can reduce the quality of the processed product .

25. *In mixed salads, the quality of the total product is only as good as that of the most perishable component. This also applies to cleaned and washed spinach and other products where differences in leaf age or physical damage to leaves may yield a product of non uniform perishability. • *Quality assurance programs, long regarded as essential in the processed food industry, are difficult to apply to horticultural crops and the corresponding minimally processed products. Fresh horticultural products have not yet been subjected to the same sanitation, labeling, and shelflife requirements as other processed foods.

26. 2. Jordanian practice regarding the minimally processed fruits and vegetables • * Minimally processed fruits and vegetables industry • in Jordan is still at its infancy stage. It started from about 10 years only. No high or sophisticated technology for minimally processed fruits and vegetables is available in the country except for potato and peas. The other vegetables are processed on house-hold scale (Table 1).

27. *Number of house-hold producers is about 10 whereas number of processing plants is only 2. • *No research activity regarding the minimally processed fruits and vegetables is available in the country.

28. *It can be observed from Table 1 that Jewish mellow is the major minimally processed vegetable followed by potato, peas, corn and squash.*Small quantities (100 tones annually) are produced from each of eggplant, carrot, turnip and spinach. Exporting activity is available for two of vegetables i.e potato strips and Jewish mellow.

29. *Processing operations for minimally processed vegetables include cleaning (spinach), shelling (peas), trimming (turnip and corn), separating of leaves from stems (Jewish mellow), removing of leaves (corn and turnip), peeling (potato and carrot), freezing (potato and peas) and dicing (spinach).*The Jordanian minimally processed vegetables industry is season dependent i.e more quantities in summer compared with winter. As a result number of retailers for minimally processed vegetables in winter is about 25 while in summer they reach to about100 and are being concentrated in the capital (Amman) and other large cities i.e Irbid, Zarqa, Karak and Aqaba.

30. *The Jordanian minimally processed vegetables industry is season dependent i.e more quantities in summer compared with winter. As a result number of retailers for minimally processed vegetables in winter is about 25 while in summer they reach to about100 and are being concentrated in the capital (Amman) and other large cities i.e Irbid, Zarqa, Karak and Aqaba.

31. Table1.Jordanian production of minimally processed vegetables • 31

32. Table1continued.Jordanian production of minimally processed vegetables