Approaches of Gamma Irradiation for Extending the Shelf Life of Fruits

KHALID GUL1', NISAR AHMAD MIR2, BASHARAT YOUSUF3, MAMTA BHARADWAJ2, and PREETI SINGH4

'Department ot Food Science and Technology,

Institute of Agriculture and Lite Sciences,

Cyeongsang National University, Jinju 660-701, South Korea

2Department of Food Engineering & Technology,

Sant Longowal Institute of Engineering & Technology,

Longowal, Punjab 148106, India

3Department of Post-Harvest Engineering and Technology,

Faculty of Agricultural Sciences, Aligarh Muslim University,

Aligarh 202002, India

4Chair Food Packaging Technology, Technical University of Munich, Freising-Weihenstephan 85354, Germany

'Corresponding author. E-mail: This email address is being protected from spam bots, you need Javascript enabled to view it

ABSTRACT

Postharvest quality loss of agricultural produce during storage is a global concern. Irradiation of the fresh produce is being widely used to extend shelf life, as quarantine measure, and is gaining increased importance. Irradiation with ionizing energy is also effective in causing death of many common pathogens that include E. coli 0157:H7, Listeria monocytogenes, Salmonella, and Vibrio spp. and are responsible for various foodborne diseases. Irradiation of fruits has addressed problems concerning short shelf-life, high initial microbial loads, insect and pest management in the supply chain, and safe consumption. Irradiation preservation technique is efficient, safe, no pollution, no residues, and does not result in deterioration of functional, textural, and nutritional qualities of the fruits. Synergistic effects of hurdle technology can reduce the amount of reagent and irradiation dose, to increase the shelf life and ensure the safety of food. With the development in the food sciences, irradiation processing of agricultural produce, especially fruits can further improve people’s living standards and will be of great significance in commercial production.

INTRODUCTION

Fresh fruits and vegetables are highly appreciated due to being rich in vitamins and antioxidants, along with the convenience for the consumers. The consumption of fresh and fresh-cut fruits and vegetables has increased rapidly in the past decade. However, fresh fruits undergo post-harvest losses and deteriorate as a result of physiological aging, biochemical changes, high respiration rate, and high ethylene production, and act as a growth media for micro-organisms associated with outbreaks of food-borne illnesses (El-Ramady et al., 2015; Qadri et al., 2015).

For reduction in postharvest losses and to extend the shelf life of fresh produce, different postharvest management teclmiques have been widely practiced which include low-temperature storage, controlled atmosphere packaging and surface treatment with chemicals. Some commonly used treatment teclmiques include blanching, chlorination, and acidification. Blanching process involves exposure of plant tissues to heat, either steam or hot water, for a defined time period and at a specific temperature, primarily to inactivate the enzymes. However, blanching may cause various undesirable changes, such as changes in color and texture. Heat treatment results in the destruction of the cellular structure of fruits thereby decreasing firmness. Chlorination is applied to prevent cross-contamination and enhance the efficiency of washing; however, it does not eliminate pathogens (Beuchat and Ryu, 1997). Reduction in pH can be achieved by adding certain acids such as acetic, lactic, sorbic, and benzoic to control the growth of micro-organisms. However, chlorination and acidification treatments are often accompanied by an undesirable acid or chlorine taste. Controlled atmosphere packaging and low-temperature storage are effective and popular strategies to extend the shelf life of fresh commodities (Brody et al., 2011). However, it has been documented that these methods may not be able to control certain pathogenic fungi and bacteria in the prevailing storage conditions.

Irradiation has been successfully applied as an effective alternative treatment for microbial disinfection and shelf life extension of fresh produce (Prakash et al., 2000). Food irradiation is a process in which food is exposed to ionizing radiations, such as gamma rays emitted from the radioisotopes Co60 and Cs137, or, high energy electrons and X-rays (Farkas, 2006). These types of radiations are applied because

  • (a) They produce desirable food preservative effects.
  • (b) They do not induce radioactivity in foods or packaging materials.
  • (c) Their availability and costs are such that they allow commercial use of the irradiation process (Farkas, 2004; Arvanitoyannis, 2010).

Gamma rays from radioactive nuclides, energetic electrons from particle accelerators, and X-rays emitted by high-energy electron beams are good sources of ionizing energy for applications in food preservation due to then- sufficient penetration power through any solid materials with substantial thicknesses. Food irradiation, where ever used in this chapter will mostly mean gamma irradiation and/or e-beam technologies only. Food irradiation may be considered as a second big breakthrough after pasteurization. Irradiation results in minimal modification of flavor, color, nutrients, taste, and other quality attributes of foods. The most common and conventional use of food irradiation involves the exposure of food to cobalt-60 (or much infrequently of cesium-137) radioisotopes to extend shelf life and to enhance safety (Farkas and Mohacsi-Farkas, 2011).

Irradiation eliminates microbial contamination, inhibits the germination of crops, and delays the ripening rate of fruits and vegetables, thereby ensuring safety and extending the shelf-life (Lacroix, 2014; Lung et al., 2015). It is considered as a safe and effective postharvest treatment by several international authorities (WHO, 1999), and can be applied as an alternative to chemical fumigants. Extensive researches, particularly regarding the use of low irradiation doses on foods, have been reported since it was considered as a safe treatment for food (Roberts, 2014). Despite being an extensively studied food processing technique, food irradiation has not still received commercial implementation due to public misunderstanding toward it (Kong et al., 2014).

Research studies have shown that people tend to accept irradiated foods after giving them appropriate information on their safety and quality (Eustice and Brtilm, 2006; DeRuiter and Dwyer, 2002). This improves the consumers’ acceptance of food irradiation. It is, therefore, important to aware consumers and provide them recent information in this field. However, some retailers falsely believe consumers will not prefer irradiated food, even though irradiated foods, especially imported fruits and vegetables, have been on store shelves and successfully being sold for several years. This chapter summarizes the progress and application of irradiation of fruits, their safety, and quality.

IRRADIATION OF FRUITS

Irradiation of fresh and fresh-cut fruits is widely utilized now in numerous countries. There is an increasing trend both in developed countries and many developing countries to centrally process fresh fruits, properly packaged, for distribution and marketing. Changes occurring in demographics, lifestyles, and eating habits are some of the reasons for the growing demands for fresh- cut and other minimally processed agricultural produce.

The nonresidual character of ionizing radiation is an important advantage as strong legislations have come up to reduce the use of chemicals for fruits. Food irradiation is considered as a safe and effective technique by the World Health Organization (WHO), the Food and Agriculture Organization (FAO), and the International Atomic Energy Agency in Vienna (Arvanitoy- annis et al., 2009). Ionizing radiations in food processing effectively damage the DNA so that living cells become inactivated. Therefore, micro-organisms and insect cannot reproduce resulting in various preservative effects. The advantage with irradiation is that radiation-induced other chemical changes in foods are negligible (Thayer, 1990). Irradiation technology has successfully reduced postharvest losses and controlled the insects and the micro-organisms in stored product. Different fruits have been shown to have enhanced shelf life postirradiation. Table 8.1 summarizes recent studies on the use of irradiation for fresh fruits.

TABLE 8.1 Fruits Irradiated in Recent Times Along With the Irradiation Dose.

Commodity

Irradiation dose/type

References

Apple

0-1.32 kGy; y-rays

Fan et al. (2011)

0-1.5 kGy; y-rays

Al-Bachir (1999)

0.5-2 kGy; y-rays

Foaad and Fawzi (2003)

0-6 kGy; y-rays

Wang and Chao (2003)

0-240 mJ-cur2, UV-C

Islam et al. (2016)

219 kJ in"2, UV-B

Assumpcao et al. (2018)

TABLE 8.1 (Continued)

Commodity

Irradiation dose/type

References

20-160 Gy; y-rays

Zhan et al. (2014)

0-1 kGy; y-rays

Song et al. (2012)

0-5 kGy; y-rays

Wanget al. (1993)

0-800 Gy; y-rays

Perez et al. (2009)

0.3-0.9; y-rays

Drake et al. (1999)

150-900 Gy; y-rays

Drake et al. (2003)

Apple (pectin)

0-10 kGy; y-rays

Sajoberg (1987)

Blueberry

2.5 kGy; y-rays

Wanget al. (2017)

150 and 300 Gy; y-rays

Lires et al. (2018)

150, 400, and 1000 Gy; y-rays

Golding et al. (2014)

0.5-3 kGY; y-rays

Wang and Meng, (2016)

1.0-3.2 kGy; e-beam

Moreno et al. (2007)

0.5-3 kGy; e-beam

Kong et al. (2014)

150 and 300 Gy; y-rays

Lires et al. (2018)

Banana

0-2 kGy; y-rays

Gloria and Adao (2013)

Chestnut

0.27 and 0.54 kGy; y-rays

Antonio et al (2011)

Cherry

0-0.9 kGy; e-beam

Drake and Naven, (1997)

Grapefruit

0-700 Gy; y-rays

Patil et al. (2004)

0-0.3 kGy; y-rays

Vanamala et al., (2007)

Pear

0.8-2 kGy; y-rays

Wani et al. (2008)

0-800 Gy; y-rays

Perez et al. (2009)

150-900 Gy; y-rays

Drake et al. (2003)

Hazelnut

0.5-1.5 kGy; y-rays

Guler et al. (2017)

Strawberry

1-10 kGy; y-rays

Bidawid et al. (2000)

0-900 Gy; y-rays

Maraei and Elsawy (2017)

3.6 kGy; y-rays

Lima et al. (2014)

1.2 and 2 kGy; y-rays

O’Connor and Mitchell, (1991)

2 kGy; y-rays

Hussain et al. (2012)

0-2 kGy; e-beam

Yu et al. (1995)

1 kGY; y-rays

Jouki and Khazaei, (2014)

400 Gy; y-rays

Serapian and Prakash (2016)

2.0 KJ nr2; UV-C

Jin et al. (2017)

0.6-3.6 KJ nr2; UV-C

Xie et al. (2016)

4.1 KJ nr2; UV-C

Pombo et al. (2009)

4.1 KJ nr2; UV-C

Li et al. (2014)

4.1 kJ/m2 UV-C

TABLE 8.1 (Continued)

Commodity

Irradiation dose/type

References

Mandarin

0.6; y-rays

Zhang et al. (2014)

510 and 875 Gy; X-ray

Rojus-Ardugo et al. (2014)

Mango

100-200 Gy; y-rays

Janave and Sharma (2005)

150-300 Gy; y-rays

Gomez-Simuta et al. (2017)

5 kJ ur:; UV-B

Ruan et al. (2015)

2.5-10 kJ m :; UV-C

Santo et al. (2018)

0.4 and 1 kGy; y-rays

Sabato et al. (2009)

0-0.6; y-rays

Uthairatanakij et al. (2006)

1-3.1 kGy; e-beam

Moreno et al. (2006)

0.5- 0.95 kGy; y-rays

Lacroix et al. (1990)

0-2 kGy; y-rays

Youssefet al. (2002)

0.3-10 kGy; y-rays

Mahto and Das (2013)

Guava

0-1750 Gy; y-rays

Zhao et al. (2017)

 
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