机械类文献翻译保持微创新鲜已加工果蔬的微生物和感官质量的新兴技术1.docx

1、机械类文献翻译保持微创新鲜已加工果蔬的微生物和感官质量的新兴技术1文献翻译（20*届本科） 学 院： 食品学院 专 业： 食品科学与工程（物流工程） 班 级： 高地一班 姓 名： xxx 学 号： xxx 指导教师： xxx20*年5 月Emerging technologies for keeping microbial and sensory quality of minimally fresh processed fruits and vegetables The emphasis in post-harvest fruit protection against quality attr

2、ibutes losses, physiological disorders, diseases and insects has shifted from using agro-chemicals to various alternative techniques, including biological control, cultural adaptations and physical methods such as controlled atmosphere (CA), MAP and irradiation. Given the restrictions of chemical us

3、e in plant foods and because many of them cause ecological problems or are potentially harmful to humans and may be withdrawn from use, the advantage of these alternative techniques is that no chemicals are involved (Arts, 1995; Graham and Stevenson, 1997; Reddy et al., 1998; Mathre et al., 1999; Sa

4、nz et al., 1999; Daugaard, 2000; Harker et al., 2000; Marquenie et al., 2003). Additionally, preservation techniques are becoming milder in response to demands of consumers for higher quality, more convenient foods that are less heavily processed and preserved and less reliant on chemical preservati

5、ves (Abee and Wounters, 1999). The unique way to assure microbial and sensory quality of minimally fresh processed plant products relies on refrigerated storage and distribution, although combination of refrigeration and subinhibitory preservation techniques could prolong their shelf-life. As mentio

6、ned above, many non-conventional methods are now being investigated; however, there are some limitations to their application since some methods are not applicable to fresh-cut fruits and vegetables because of damage to plant tissue but only to liquid foods such as fruit juices (Carlin and Nguyen-th

7、e, 1997). Therefore, in this section those techniques that can be used to preserve fresh processed plant foods will be revised.The most critical step in the production chain of minimal fresh processing of fruits and vegetables is washing-disinfection. For this reason, special attention to the altern

8、ative sanitizing agents as well as the new technologies for disinfection of these commodities will be given. To develop or improve washing and sanitizing treatments, special attention should be paid to the compatibility of treatments with commercial practices, cost, absence of induced adverse effect

9、s on product quality and the need for regulatory approval and consumer acceptance (Sapers, 2001). Some alternatives to sanitizing agents are: O3, ClO2, peracetic acid (about 90100 ppm), H2O2, organic acids (acetic, lactic, citric, malic, sorbic and propionic acids at 300500 mg/ml), electrolysed wate

10、r, radio frequency, hot water treatments and UV-C radiation (Adams et al., 1989; Masson, 1990; Castaer et al., 1996; Toms-Barbern et al., 1997; Delaquis et al., 1999, 2000, 2004; Sapers, 2001; Suslow, 2002; Jacxsens, 2002; Aguayo, 2003; Allende, 2003).1. Hydrogen peroxideTreatments of hydrogen perox

11、ide (H2O2) seem to be a promising alternative to chlorine for disinfecting minimally fresh processed vegetables (Soliva-Fortuny and Martn-Belloso, 2003). H2O2 is generally recognized as safe (GRAS) for some food applications, but has not yet been approved as an antimicrobial wash. It does not produc

12、e residues since it is rapidly decomposed by the enzyme catalase to water and O2 (Sapers, 2001). Various experimental antimicrobial applications of H2O2 for foods have been described, including preservation of vegetable salads, berries and fresh-cut melons (Hagenmaier and Baker, 1997) since it reduc

13、es microbial populations and extends the shelf-life without causing loss of quality. Sapers and Simmons (1998) recommended its use for fresh-cut melon as it extended the shelf-life for 45 days in comparison to chlorine treatments. However, they demonstrated that H2O2 is injurious to some commodities

14、, causing bleaching of anthocyanins in mechanically damaged berries. H2O2 vapour delayed or reduced the severity of bacterial soft rot in fresh processed cucumber, green bell pepper and zucchini, but no effect on spoilage of fresh-cut broccoli was found (Hagenmaier and Baker, 1997). Additionally, an

15、 extended shelf-life was found in fresh processed cucumbers, green bell peppers and zucchini after washing in a 510 per cent solution of H2O2 for 2 min (Sapers and Simmons, 1998). It means that the applicability of H2O2 to a broad range of minimally fresh processed vegetables should be determined, e

16、specially with commodities that are subject to rapid spoilage.2. Acidic electrolysed waterThis is a new disinfectant technique for fresh produce that has been shown to be efficient due to its antimicrobial and antiviral activities for fruit and vegetables (Izumi, 1999; Koseki and Itoh, 2000). Electr

17、olysis of water containing a small amount of sodium chloride generates a highly acidic hypochlorous acid solution containing 10100 ppm of available chlorine. Koseki et al. (2001) found that acidic electrolysed water (pH 2.6, oxidation reduction potential, 1140mV; 30 ppm of available chlorine) reduce

18、d viable aerobes in shredded lettuce by 2 log cfu/g within 10 min, showing a higher disinfectant effect than ozonated water. They reported that the use of this new technique could be applicable for food factory hygiene, meaning that the use of acidic electrolysed water at home or restaurant kitchen

19、just before eating fresh fruits and vegetables could prevent poisoning. According to this, Park et al. (2002) reported population reductions on lettuce leaves exceeding 2.49 log units for E. coli O157:H7 and L. monocytogenes and Horton et al. (1998) reported population reductions of E. coli O157:H7

20、on apples of 3.74.6 log units cfu/g. However, Izumi (1999) only found 1 log unit cfu/g reduction in the microbial population of fresh-cut vegetables.3. Chlorine dioxide Chlorine dioxide (ClO2) is a strong oxidizing agent (about 2.5 times the oxidative capacity of chlorine) having a broad biocide eff

21、icacy (Singh et al., 2002), including a good biofilm penetration. To date, the FDA (USFDA, 1998) has allowed the use of aqueous ClO2 in washing of uncut and unpeeled fruit and vegetables. However, ClO2 is unstable and it must be generated on-site and can be explosive when concentrated (Jacxsens, 200

22、2). Zhang and Farber (1996) found that the initial microbial load decreased by 1 log cycle of cfu/g for shredded lettuce inoculated with L. monocytogenes at levels of 5 mg/l ClO2 in aqueous solution. However, Reina et al. (1995) found that bacterial populations present on fresh processed cucumbers w

23、ere not greatly influenced by ClO2 treatment, even at concentration of 5.1 mg/l. More recently, Singh et al. (2002) found that increasing the concentration of ClO2 in deionized water (5 mg/l for 1 and 5 min) resulted in a decrease in E. coli O157:H7 population on lettuce and baby carrots in comparis

24、on to washing with deionized water (control) for the same period. Increasing the washing period from 1 to 15 min with aqueous ClO2 (5 mg/l) showed no significant reduction in the population of E. coli O157:H7 on shredded lettuce. However, after washing baby carrots a reduction in E. coli O157:H7 was

25、 found.4. Organic acids Several organic acids have been tested as alternative disinfectants to sanitize fresh-cut vegetable surfaces (Hilgren and Salverda, 2000). They may retard and/or prevent the growth of some microorganisms (Beuchat, 1998). Their antimicrobial activity is not generally due to ki

26、lling of the cells but they affect the cells ability to maintain pH homeostasis, disrupting substrate transport and inhibiting metabolic pathways (Seymour, 1999). Peracetic acid has been recommended for treatment of process water (Hilgren and Salverda, 2000); however, population reductions for aerob

27、ic bacteria, coliforms, yeast and moulds on fresh-cut celery, cabbage and potatoes, treated with 80 ppm peracetic acid, were less than 1.5 log units cfu/g (Forney et al., 1991). Wright et al. (2000) obtained a 2 log units cfu/g reduction in apple slices inoculated with E. coli O157:H7 using 80 ppm p

28、eracetic acid, with an interval of 30 min between inoculation and treatment.On the other hand, Wisniewsky et al. (2000) found a reduction of less than 1 log unit cfu/g at the same concentration but in an interval of 24 h. Citric acid has been proposed as a very good coadjutant to the washing of fres

29、h-cut fruit and vegetables due to its antibrowning power. It is a phenolase Cu-chelating agent and the inhibition of PPO was attributed to its chelating action (Jiang et al., 1999). Santerre et al. (1988) reported that application of citric acid can prevent browning of sliced apple thus extending sh

30、elf-life and it was shown that the combination of citric acid and ascorbic acid exhibited even more beneficial effects (Pizzocaro et al., 1993). Additionally, Jiang et al. (2004) found that the application of citric acid was effective in extending shelf-life and maintaining the quality of fresh-cut

31、Chinese water chestnut slices during storage.5. Ozone Ozone (O3) is a strong oxidant and potent disinfecting agent and, when it is applied to food, it leaves no residues since it decomposes quickly. The biocide effect of O3 is caused by a combination of its high oxidation potential, reacting with or

32、ganic material up to 3000 times faster than chlorine (EPRI, 1997). Even though it is new for the USA, it has been utilized in European countries for a long time (Guzel-Seydima et al., 2004). For instance, it has been commonly used as a sanitizer in water treatment plants since the early 1900s (Gomel

33、la, 1972) and also for disinfection of swimming pools, sewage plants, disinfection of bottled water and prevention of fouling of cooling towers in Europe (Gomella, 1972; Rice et al., 1981; Legeron, 1982; Schneider, 1982; Echols and Mayne, 1990; Costerton, 1994; Videla et al., 1995; Strittmatter et al., 1996). In 1997,