Sodium caseinate reduces the swelling of konjac flour: A further examination

Abstract

Konjac flour can quickly swell and dissolve in a short time, leading to extremely high viscosity and easily agglomerative phenomenon. Such characters limit its application as ingredients in brewed foods and there is a high demand to restrict its swelling. Ethanol is usually adopted as a swelling inhibitor but it cannot be applied in the food industry. In this study, two types of milk (full-fat milk and low-fat milk) were selected and the swelling rates of konjac flour in these milk systems were measured. The results showed that the swelling rate of konjac flour significantly decreased. The konjac particles quickly cracked and dissolved in water within 3 min while only swelled in milk systems. To reveal which component in milk played a key role, we further studied the influence of the three components (lactose, whey protein isolate and sodium caseinate) on the swelling limitation of konjac flour. Sodium caseinate was found to be the strongest component than lactose and whey protein isolate in limiting the swelling of konjac flour. Our study revealed that casein was the crucial actor in inhibiting konjac flour swelling in milk and simulated milk system, indicating a new way to better control its swelling behavior in aqueous solution.