Postharvest preservatives

This part of the chapter describes HPLC techniques for the separation and determination of preservatives, as follows S02, postharvest preservatives (PPs), benzoic acid (BA), sorbic acid (SA), and the ethyl, methyl, propyl esters of 4-hydroxybenzoic acid (EsHBA) and 5-nitrofury-lacrylic acid (5-NFA). The propionic, lactic, acetic acids are discussed in the chapter on organic acids. 

Table 4 HPLC Systems Used for Determination of Postharvest Preservatives... 

A procedure for the analysis of fruit for residues of postharvest preservatives and ethoxyquin was described by Gieger (132). Residues were extracted with dichloromethane via ultrasonic treatment. The extracts were analyzed on a C,8 5-/zm column, with methanol/0.01 M ammonium acetate (61 39) as a mobile phase adjusted to pH 7.5-7.7. Recovery for ethoxyquin was 65-78%, with a detection limit of approximately 0.05 mg/kg. 

Use Insecticide, antioxidant, flex-cracking inhibitor, postharvest preservation of apples (scald inhibitor). 

The antioxidant capacity retained in carrots washed with ASC could be attributed to retention of phenol and flavonoid compounds as well as carotene content (Ruiz-Cruz and others 2007). These results suggest that the use of sanitizers such as ASC is helpful in preserving the antioxidant capacity of carrots. Similar ORAC values were observed between different sanitizers and both water conditions, without significant changes. This is a clear example of a postharvest treatment maintaining the nutritional value of produce. 

Ayala-Zavala JF, del-Toro-Sanchez L, Alvarez-Parrilla E, Soto-Valdez H, Martin-Belloso O, Ruiz-Cruz S and Gonzalez-Aguilar GA. 2008b. Natural antimicrobial agents incorporated in active packaging to preserve the quality of fresh fruits and vegetables. Stewart Postharvest Rev 4 1—9. 

Gorny J, Hess-Pierce B, Cifuentes R and Kader A. 2002. Quality changes in fresh-cut pear slices as affected by controlled atmospheres and chemical preservatives. Postharvest Biol Technol 24 271-278. 

Control of stem-end rots caused by A. citri, D. natalensis, and P. citri with postharvest applications of the growth regu-lators 2, 4-D and, occasionally, 2,4,5-T is attributed to preservation of the green button and prevention of abscission (106,... 

Use Industrial preservative (bactericide and fungicide), mold inhibitor for apples and other fruit (postharvest). 

Due to the difficulties of postharvest storage, most of the mushrooms are preserved by heat drying. The drying process has to be conducted slowly in order to produce the characteristic sulfurous note of this mushroom. 

Vitamins. Vitamins, which are important nutritional components of fruits and vegetables, can also act as antioxidants, pigment relatives and cofactors for numerous enzymatic reactions. They are subject to decomposition after harvest so proper postharvest treatment is crucial to their preservation. The role of vitamins in the postharvest physiology of vegetables has been recently reviewed (6). 

One of the prime goals of food processing or preservation is to convert perishable foods snch as fruits and vegetables into stabilized products that can be stored for extended periods of time to reduce their postharvest losses. Processing extends the availability of seasonal commodities, retaining their nutritive and esthetic values, and adds variety to the otherwise monotonous diet. It adds convenience to the products. In particular it has expanded the markets of fruit and vegetable products and ready-to-serve convenience foods all over the world, the per capita consumption of which has rapidly increased during the past two to three decades. 

Polyamides, Polyesters and other polymers. Polypropylene is p>art of the Polyolefin group and used largely in MAP, in both forms continuous and perforated. Sanz et al. (1999) studied the quality of strawberries packaged with polypropylene film, with proper perforations, during commercial postharvest practices. They concluded that perforated-mediated MA packaging helped to preserve fruit ripeness degree better, maintaining its nutritional value, measured as ascorbic acid content. 

Akamine, E.K. and Moy, J.H. (1983) Delay in postharvest ripening and senescence of fruits. In preservation of food by ionizin radiation (Josephson and Peterson eds.) CRC press, Boca Raton, Florida... 

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