Characterization of novel plant-based gel structures fabricated from hazelnut using combination of anionic and neutral gums

Abstract

Although the production of plant-based dairy analogues has increased recently, structural defects such as weak and unstable texture with syneresis have been major obstacles to consumer acceptance. Hydrocolloid gums can play a crucial role to improve the structure of these products. This study aimed to use combinations of anionic and neutral gums for stabilization of an acidic hazelnut-based matrix towards structure development for plant-based products. Aqueous solutions of six different gum combinations, locust bean gum (LBG) or guar gum (GG) as neutral along with alginate (AL), low methoxyl pectin (LMP) or xanthan gum (XG) as anionic gums, were mixed with an acidic hazelnut slurry. Heat-induced gelation behavior of the mixtures and also the solutions of the gums was investigated. Rheological, textural, water holding capacity, zeta potential, FTIR and SEM analyses were performed in the samples. Except for the samples with LMP, the negativity of the zeta potential values of the gum solutions was reduced by mixing with the hazelnut slurry pointing to electrostatic interactions. Particle size of solutions of all gum combinations increased by mixing with the hazelnut slurry. All gum combinations and their mixtures with the hazelnut slurry formed gels with 100 % water holding capacity and different viscoelastic and textural properties. Stable and strong gels were obtained from the mixtures containing combinations of LMP or XG with neutral gums presenting firmness values of about 2 N and 5 N, respectively. The mixtures including AL weakened during cold storage with up to 4-fold reduction in elastic modulus. Heating of the gels induced weakening and flow of all the samples with the lowest and the highest melting temperature observed in the samples with XG (50 °C) and LMP (73 °C), respectively. Results from FTIR and SEM analyses supported the dominant role of gums in the formation of a gel network in the hazelnut matrix. This work demonstrates that stable and thermoreversible gel structures can be formed by using XG or LMP along with neutral gums in acidic plant-based products.