Elsevier

LWT

Volume 116, December 2019, 108539
LWT

Short communication
Gamma irradiation of common beans: Effect on nutritional and technological properties

https://doi.org/10.1016/j.lwt.2019.108539Get rights and content

Highlights

  • Ionizing irradiation can be used on common beans with positive impact.

  • Irradiation did not affect protein, fat, and ash content of cooked beans.

  • Irradiation reduced the phytic acid content and cooking time.

  • Irradiation improved the protein in vitro digestibility.

Abstract

This work aimed studied the effect of ionizing irradiation on the nutritional and technological properties of cooked Carioca beans (Phaseolus vulgaris). The dry beans were irradiated with different doses (1, 5 and 10 kGy) of γ-radiation using 60Co as source. The composition and nutritional properties (protein, fat, ash, tannin, phytic acid content and protein in vitro digestibility) of the cooked beans were analyzed, with and without previously soaking process. In addition, the technological properties (hydration index, cooking time and color) of the beans were also evaluated. The results showed that protein, fat, ash and tannin content, as well as color, were not affected by irradiation, while the phytic acid was significantly reduced by the irradiation. Further, hydration index was slightly reduced only by using 10 kGy suggesting probable structure changes. Irradiation reduced the cooking time of the beans, as higher irradiation doses were used, which was related with the reduction on the phytic acid content. Moreover, protein in vitro digestibility was enhanced by irradiation. In conclusion, irradiation up to 10 kGy can be safely used to improve the shelf life of common beans without degradation of nutritional components, reducing some antinutrients content, improving protein digestibility and reducing the cooking time.

Introduction

Beans are widely consumed due to their nutritional and sensorial properties, being the second most consumed crop in the world (Singh, 2017). In fact, this food is a good source of proteins, dietary fiber, starch (Siddiq & Uebersax, 2012) and iron (Priscila Brigide, Canniatt-Brazaca, & Silva, 2014). Beans are commonly harvested and marketed dried. This is advantageous by assuring their physical, chemical and microbiological stability, as well as facilitating their transportation and storage. However, despite this, the bad conditions of growth and storage can cause insect and fungi contamination of the beans. Therefore, one way to avoid fungal and bacterial development as well as insect reproduction is the application of ionizing radiation (O'Hara, 2012; Thalita, Armando, & Luís, 2014).

The irradiation consists of the exposure of a material, such as food to ionizing radiation (alpha, beta, gamma, x-ray or energetic electrons) for certain time. This ionizing radiation is mainly produced by radioactive sources or energetic electrons generator (Marshall, 2012). The irradiation dose is expressed in Grays (Gy), which depends on the radioactive source energy and the exposure time, and equivales to 1 J of absorbed energy per 1 kg of sample (Mahapatra, Muthukumarappan, & Julson, 2005). Depending on the purpose, different irradiation doses are used. For instance for the inhibition of sprouting, insect disinfection and delay of ripening, doses below 1 kGy are used; for reduction of microorganisms load, changing technological properties of food, doses from 1 to 10 kGy are used; and for commercial sterilization of low acid foods and viruses eliminations doses from 10 to 50 kGy are used (Ehlermann, 2016).

The use of irradiation on grains can be considered as an attractive alternative to the chemical treatments to control fungal and insect contamination. Thereby, it is very important to evaluate if this technology affects the beans components and technological properties. In fact, ionizing radiation was already used on some legume grains as fava beans (Osman et al., 2014), mung beans (Khattak & Klopfenstein, 1989), cowpeas (Lima, Souza, Godoy, França, & Lima, 2011), and common beans (Villavicencio, Mancini-Filho, Delincée, & Greiner, 2000), evaluating its effect in some selected nutritional and/or anti-nutritional components. However, due to the importance and advantage of the irradiation on beans, and due to some controversial results, more studies should be conducted using other beans, different irradiation doses and evaluating nutritional and technological properties of interest for the consumer.

In addition, it is also necessary to evaluate the combined effect of irradiation with common unit operations during processing, such as soaking, since it is widely used before the cooking process (Miano and Augusto, 2018). Most of the studies in the literature focus on the individual effects of irradiation or soaking on cooking time or on nutritional properties before cooking (Çelik, Basman, Yalçin, & Köksel, 2004; Köksel & Çelik, 2001). Therefore, the combined effects on nutritional quality of beans requires further investigation. Moreover, many works in the literature perform the irradiation process in the rehydrated grain, although the grain is sold dry for the consumer. In fact, there is any work in the literature that performed the irradiation process in the dry beans, evaluating them after hydration and cooking – although this is the most logical way of processing and consumption.

Consequently, the present work aimed to study the effect of different irradiation doses on some properties of carioca beans (Phaseolus vulgaris) after soaking and cooking processes.

Section snippets

Sample preparation

Common beans (Phaseolus vulgaris), carioca variety, IAPAR 81 cultivar harvested from Parana State (Brazil) were used for the present work. The beans were preselected discarding the ones with cracks, without seed coat and with stains. For irradiation, 500 g of beans were packed in polyethylene bags and then submitted to radiation doses of 0 (control), 1, 5 and 10 kGy, using a Cobalt-60 multipurpose irradiator (installed at the Institute of Energy and Nuclear Research – IPEN – SP, Brazil), at

Results and discussion

Fig. 1 shows the effect of the irradiation doses on the chemical composition of cooked beans that were presoaked (S + C) or not (C). In fact, most of the chemical composition of carioca beans (ash content, protein content, fat content and tannins) were not significantly affected by the irradiation (p < 0.05). This result is in agreement with other works as for fava beans using 1 kGy (Osman et al., 2014), for cowpea using 10 kGy (Lima et al., 2011) and for common beans and green grams using

Conclusions

In conclusion, this work demonstrated that by irradiating dry beans at doses up to 10 kGy did not cause significant change on the fat, protein and ash content of common beans after cooking. However, this technology enhanced protein digestibility and reduced the cooking time as well as it reduced the phytic acid content, which is an antinutrient responsible to the protein and iron bioaccessibility reduction. Therefore, it is strengthened the idea that ionized radiation can be applied on beans to

Acknowledgments

The authors are grateful to the National Nuclear Energy Commission (CNEN, Brazil) for the financial assistance and D.C. Lima Scholarship; the National Council for Scientific and Technological Development (CNPq, Brazil) for the productivity grant of P.E.D. Augusto (306557/2017-7).

References (33)

  • P. Brigide et al.

    Nutritional characteristics of biofortified common beans

    Food Science and Technology (Campinas)

    (2014)
  • S. Çelik et al.

    Effects of irradiation on protein electrophoretic properties, water absorption and cooking quality of dry bean and chickpea

    Food Science and Technology Research

    (2004)
  • A.R. De Boland et al.

    Identification and properties of phytate in cereal grains and oilseed products

    Journal of Agricultural and Food Chemistry

    (1975)
  • V. Iyer et al.

    Quick-cooking beans (Phaseolus vulgaris L.): I. Investigations on quality. [journal article]

    Plant Foods for Human Nutrition

    (1980)
  • A.B. Khattak et al.

    Effects of gamma irradiation on the nutritional quality of grain and legumes. I. Stability of niacin, thiamin, and riboflavin

    Cereal Chemistry

    (1989)
  • H. Köksel et al.

    Quality evaluation of gamma-irradiated food legumes. GIDA –

    The Journal of Food

    (2001)
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