Elsevier

LWT

Volume 91, May 2018, Pages 191-197
LWT

Effect of high pressure treatment on functional, rheological and structural properties of kidney bean protein isolate

https://doi.org/10.1016/j.lwt.2018.01.054Get rights and content

Highlights

  • Kidney bean protein isolates were modified by high-pressure treatment.

  • Rheometry was employed to elucidate the pressure assisted protein denaturation.

  • Particle sizes of protein isolates varied with HP treatment.

  • The protein band intensity decreased with intensity of high-pressure.

Abstract

Impact of high pressure (HP) treatment (200, 400 and 600 MPa for 15 min) on the functional, structural and rheological properties of red kidney bean protein isolate (KBPI) was investigated. HP treatment significantly influenced the water holding capacity, foaming, emulsifying properties, at above 600 MPa. FTIR spectroscopy traced the changes in the secondary structure (β-sheets) with the pressure treatment. Oscillatory rheological measurement of the HP-treated KBPI dispersions showed a significant increase in the G′ and the G″ with increasing frequency, and a distinct thermal denaturation temperature (Td). DSC measurement showed a slightly higher Td values (105 °C) than rheometry. SDS-PAGE profiles revealed that the HP had a little effect on the protein structure when samples were treated below 600 MPa. The potential of plant-derived proteins have increased tremendously, and the developed KBPI could be used as one of the functional and nutritional ingredients in the food industry.

Introduction

Among legumes, kidney bean (Phaseolus vulgaris L.) is one the important produce, and is consumed as a cheap protein source in many developing countries. Kidney beans contain 20–30 g/100 g protein on a dry weight basis with a balanced amino acid composition; nonetheless, it is low in sulfur-containing amino acids, namely, methionine and tryptophan (Sathe, Iyer, & Salunkhe, 1981). Epidemiologic studies have revealed that consumption of kidney beans has several health benefits including the reduction of the risk of cardiovascular diseases, type II diabetes, obesity, and several/specific types of cancer (Dueñas, Martínez-Villaluenga, Limón, Peñas, & Frias, 2015).

Phaseolin or vicilin or 7-8S globulins, is the major storage protein from the kidney bean, and it constitutes about 75 and 82 g/100 g of the total seed proteins (Yin, Tang, Wen, Yang, & Yuan, 2009). It is an oligomeric protein, comprising of three polypeptide subunits namely α-, β-, and γ-phaseolin, and the molecular weight distribution ranged between 43 and 53 kDa (Romero, Sun, McLeester, Bliss, & Hall, 1975). Interestingly, vicilin present in kidney beans shows the unique structural peculiarity by low susceptibility to trypsin digestion and greater subunit homogeneity, than other vicilin components (Jivotovskaya et al., 1996, Yin et al., 2008). Because of the unique peculiarity of vicilin, the kidney bean protein isolate (KBPI) exhibits a good gelation and emulsifying ability compared to other bean isolates (Kimura et al., 2008, Tang, 2008). Additionally, KBPI have potential to be applied as an excellent food functional ingredient in various food formulations, in particular, baking, meat, and extruded products.

High-pressure (HP) treatment – a novel processing technology is commonly employed for the protein gelation purpose as an alternative of heat processing. Application of HP denatures proteins, and forms gel. Influence of HP treatment on functionality and in vitro trypsin digestibility of KBPI has been reported (Yin et al., 2008). Soy protein forms gel at and above 300 MPa by rupturing noncovalent interactions within protein molecule, and it was found that the produced gel is relatively softer than the thermally treated gel (Ahmed et al., 2007a, Dumoulin et al., 1998). The gel rigidity during pressure-assisted gelation, is mostly, measured through the evolution of the complex viscosity or by measuring the elastic modulus, G′. However, HP-induced changes in rheological and structural properties of KBPI has not been investigated so far.

The objective of this work was to study the effect of high-pressure treatment (200, 400, and 600 MPa) on the physicochemical, functional, thermal, rheological, and structural properties of freeze-dried kidney bean protein isolate.

Section snippets

Materials

Red kidney beans (Phaseolus vulgaris), cultivated in India (Cv. VL Rajma 125) were procured locally. The beans were ground using a laboratory mill (Quadrumat Junior, Brabender, Germany) followed by passing through a 297-μm sieve to obtain uniform particle size. The screened flour samples were packed in air-tight plastic containers, and stored until further use.

Preparation of kidney bean protein isolates

The kidney bean protein isolate (KBPI) was prepared following the method described by Fan and Sosulski (1974), with a minor

Physicochemical properties

The protein content of the KBPI was 80.82 g/100 g, and the value is comparable with the literature values (77–84 g/100 g) (Rui et al., 2011, Wani et al., 2015). The moisture content of the freeze dried isolate was less than 4 g/100 g by weight. The observed ash content (4.1 ± 0.3 g/100 g) is in the range of the reported values for different varieties of kidney beans (Rui et al., 2011, Wani et al., 2015). A difference in those values could be attributed to the type of kidney beans used and the

Conclusion

HP-treatment of KBPI influenced the extent of protein denaturation resulting change in functional properties. The WHC, EAI increased, and foaming properties decreased with increasing the pressure level from 200 to 600 MPa. The thermal denaturation temperature (Td) of KBPI dispersions was complimented by both rheometry and DSC measurement. A reduction and agglomeration of particle sizes were observed, the observation was pressure dependent indeed. A change in the protein secondary structure is

Acknowledgement

The authors would like to thank the Kuwait Institute for Scientific Research for funding the project (FB 121K).

References (42)

  • K. Shevkani et al.

    Structural and functional characterization of kidney bean and field pea protein isolates: A comparative study

    Food Hydrocolloids

    (2015)
  • F. Speroni et al.

    Gelation of soybean proteins induced by sequential high-pressure and thermal treatments

    Food Hydrocolloids

    (2009)
  • W.K. Surewicz et al.

    New insight into protein secondary structure from resolution-enhanced infrared spectra

    Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular

    (1988)
  • C.H. Tang

    Thermal denaturation and gelation of vicilin-rich protein isolates from three phaseolus legumes: A comparative study

    LWT-Food Science and Technology

    (2008)
  • C.H. Tang et al.

    Effect of high pressure treatment on aggregation and structural properties of soy protein isolate

    LWT-Food Science and Technology

    (2009)
  • C.H. Tang et al.

    A comparative study of physicochemical and conformational properties in three vicilins from phaseolus legumes: Implications for the structure–function relationship

    Food Hydrocolloids

    (2011)
  • E.S. Tan et al.

    A comparative study of physicochemical characteristics and functionalities of pinto bean protein isolate (PBPI) against the soybean protein isolate (SPI) after the extraction optimisation

    Food Chemistry

    (2014)
  • I.A. Wani et al.

    Physico-chemical and functional properties of native and hydrolyzed kidney bean (Phaseolus vulgaris L.) protein isolates

    Food Research International

    (2015)
  • S.W. Yin et al.

    Functional properties and in vitro trypsin digestibility of red kidney bean (Phaseolus vulgaris L.) protein isolate: Effect of high-pressure treatment

    Food Chemistry

    (2008)
  • S.W. Yin et al.

    The relationships between physicochemical properties and conformational features of succinylated and acetylated kidney bean (Phaseolusvulgaris L.) protein isolates

    Food Research International

    (2010)
  • AACC International

    Approved methods of analysis

    (2011)
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