minimal processing of fruits and vegetables.pptx

Minimal processing of fruits and vegetables

1. Minimal processing of fruits and vegetables Minimal processing of fruits and vegetables (MPFV) is the process of physically altering fresh produce to increase its functionality without changing its fresh properties.  They are also called ready-to-use, fresh-cut or pre-cut produce T he process involves sorting, cleaning, washing, peeling, trimming, and deseeding, and cutting the produce to a specific size.  MPFV must be safe, wholesome, nutritious, and have the same sensory properties as freshly prepared produce, such as; Aroma Taste T exture , and visual appeal

2. Over the last few years, global demand for minimally processed  fruits & vegetables   increased, this is so beacause of the following reasons; A growing focus on health, which includes the consumption of fresh fruits & vegetables T he increased preference for convenience. To the extent possible, consumers want healthy products for their meals, available at a good value, convenient, safe, and with good quality

3. Flow chart for preparation of minimal processed fruits and vegetables Sorting for defects Packaging and labelling Harvesting Cutting to specific size Receiving Cooling Washing and disinfection Peeling, deseeding and Trimming dipping draying Antimicrobial And A ntibrowning agents Storage & Distribution

4. Harvesting During the harvesting, the following points must be kept into consideration. Well trained person must be engaged in the selection of fresh produce of sound quality, so as to avoid its damage and contamination during handing. Handlers must ensure to use of clean and hygienic equipment's such as sharp harvesting knives, bags and padded boxes during fresh-cut processing . Mechanical harvesters are used in large operations Workers must wear clean clothes and observe sanitary measures.

5. 2. Receiving at the processing facility The receiving point for fresh fruits and vegetables in a fresh-cut processing plant is a key quality check-point that should be monitored closely . Employees receiving produce should check for defects and make note of any problems that can be relayed to the grower. At this point a decision can be made on whether or not to process the produce.

6. Large processing operations have a list of quality parameters and measurements that are recorded when fresh produce arrives at the processing facility. An inventory of stocks begins with receipt of the produce. In addition, field number, harvest crew, vehicle registration and other information also need to be recorded. This information would really help to trace it back to the field in the event of a food crisis. Large processing facilities usually have an enclosed, refrigerated dock facility for receiving produce.

7. 3.Pre-cooling Ideally , the purpose of precooling is to remove field heat prior to storage or processing so as to extend the shelf-life of the final fresh-cut produce. It can be achieved by using a number of technologies such as chilled water baths, forced air cooling, vacuum cooling and packing with ice-water mixtures. These expensive technologies are not really useful for small produce. The temperature must be kept such that it would not cause any chilling injury of the fruits and vegetables. Intact fresh produce should be segregated from the ones that have been pre-cut and washed, in a small cold storage area to avoid cross contamination between them. In addition, staff should use a First-in, First-out (FIFO) policy for managing stock rotation.

8. 4. Washing and disinfection Washing is really essential operation in MPFV and need to be carried out as soon possible. The main function of washing is to remove damaged tissues, which normally is carried out with water flumes and tanks prior to cutting and trimming. Water flume for washing and transporting fruit in a large packing house

9. Potable water is a key requirement for washing in order to preclude the transfer of contamination from water to the produce. For the issue of water conservation, many large fresh-cut processing operations treat and recycle this used water of precious commodity. But it increases the hazard of microorganisms. Thereby, recycled wash water can be treated with antimicrobial agent like HOCl for maintaining its quality. M ethods used for washing purposes of MPFV. (a). Small scale operation; washing can be carried out in a sink or under a tap with continuously circulating wash water through a filter. In most cases, two tanks are used for washing (first tank- for removal of heavy soiling and subsequent cleaner tanks with chlorinated water – for final washing ).

10. (b ). Large fresh-cut processing plants; they make use of continuous washers . In such situations, a moving conveyor picks up the produce and carries it under powerful sprays of water. Recirculation through a filter reduces the overall water consumption. The temperature, contact time, pH and chlorine concentration should be monitored for their effectiveness during washing. The measurement of ORP (oxidation reduction potential) can also be used to monitor the disinfectant level in wash water.

11. Continuous washing of pre-cut lettuce

12. For vegetables, following parameters may be used for the wash water: temperature (0-5°C), pH (4.5-5.5), chlorine concentration (50-100 ppm), ORP (650-750 ppm). During the washing process any defective produce must be removed and discarded.

13. 5.Peeling, trimming and deseeding Several kinds of equipments being used for peeling, trimming and deseeding of MPFV which includes knives for small scale, abrasive peelers and automatic trimmers for large scale. Automated peelers with abrasive rollers are used in some large processing plants for peeling potatoes and carrots. Machinery has been designed for specific high volume crops, including the use of high pressure air and lye and steam for peeling. However , for small operations, hand peeling is adequate

14. 6. Cutting operations The cutting operation may include various operations such as chopping, slicing, shredding, peeling, dicing or sectioning. These operations are done mainly by hands in many small-scale operations. The cutting dimensions are also needed to be considered. Good Hygienic Practice (GHP) must be strictly observed during cutting operations, to avoid contaminations. A proper attention should be given to employees. They must wear protective clothing including gloves, aprons and hair nets and should be well trained

15. Workers preparing and sorting cut fruit

16. 7. Sorting for defects The importance of sorting is to improve the uniformity of the finished fresh-cut product and also to enhance the shelf-life, by separation of defective products. 8 Rinsing of pre-cut fruits and vegetables It is recommended that only water of the highest quality be used for the final rinse of pre-cut fruits and vegetables. Many use chloride as disinfectant along with acid in order to maintain a pH range of 4.5-5.5 for proper action of chloride. The temperature of fresh cut is reduced with the help of ice in order to ensure that it is not a source of contamination.

17. 9 Dipping ; Produce can be optionally dipped in a solution of an acidulant /antioxidant blend consisting of a combination of ascorbic acid/citric acid for example, or in an anti-softening agent such as calcium chloride. 10 Drying ; After dipping, there is need to remove the liquid associated with the produce, prior to packaging, otherwise, it would create a mould and other microbial growth and texture deterioration problems. Some manual and mechanical methods employed for water removal from produce includes: conveyor shakers (use of the vibration) Air drying (use of forced air or polar wind) Spin-drying baskets (use of centrifugation force).

18. 11 Packaging and labeling Packaging facilitates the delivery of fresh-cut products of good quality to the consumer and also protects products from physical damage and prevents physical and microbiological contamination. Various techniques are used for packaging of MPFV such as MAP, CAP. P ackaging formats for fresh-cut fruits and vegetables (Plate 5) includes; P lastic bags T hermoformed containers with film overwraps R igid plastic containers. In addition, other packaging films used includes perforated, thin, low density polyethylene (LDPE), monolayer polyvinylchloride (PVC) and ethylene vinyl acetate.

19. Examples of packaging used for fresh-cut fruits and vegetables

20. Fresh cut fruits and vegetables

21. 1. Produce for the fresh cut processing Fresh-cut fruits: melon chunks and slices Cored and sliced pineapple A pple wedges treated with antibrowning preservatives; P eeled citrus fruits and segments; D e-capped strawberry; de-stemmed and washed grapes; sliced kiwifruits, and fruit salads, etc. Fresh-cut vegetables: S hredded lettuce S hredded and diced cabbage W ashed and trimmed spinach P eeled “baby” carrots C auliflower and broccoli florets, S liced or diced tomatoes P eeled and sliced potatoes S napped green beans T rimmed green onions, cleaned and D iced onions, and mixed salads, etc. Fresh-cut herbs are also marketed widely.

22. 2. Treatments to ensure safety

23. 3. Additives to preserve quality The marketing of minimally processed fruits and vegetables is limited by a short shelf life and rapid deterioration of their components due to tissue damage as a result of processing, e.g. washing or cutting, and the microbial growth. They can be preserved by using various techniques such as refrigeration, biopreservation , additive, mild heat treatments, disinfectants, reduction of water, microwave processing, chemical preservatives. Additives are substances added in small quantities during processing to achieve specific benefits Chemical post-cutting treatments Wounding and ethylene can initiate phenolic metabolism that ultimately leads to browning in fresh-cut tissue. Control of discoloration (pinking, reddening or blackening) or browning at cut surfaces is, therefore, a critical issue for fresh-cut producers. Outlined below are a number of strategies that may be used to reduce cut-surface discoloration and maintain the textural integrity of fresh-cut produce.

24. 5.4.1.1 Acidification: PPO most effectively catalyses cut-surface discoloration at a neutral pH (around pH 7.0). Browning can, therefore, be slowed by dipping products in mildly acidic food grade solutions of acetic, ascorbic, citric, tartaric, fumaric or phosphoric acid. Quite often, combinations of acids (for example combinations of ascorbic and citric acid) are more effective than the use of acids individually. The enzymatic browning of fresh-cut apples, cabbage, endive, lettuce, melon and pears is avoided by dipping in solution of ascorbate and citric acid ( Raju et al ., 2000). Acidification, treatments with ascorbic acid (0.2%)