Addition of Alpha-Amylase and Thickener to Blenderized Rice Provides Suitable Viscosity for Use in Nutritional Support

Background: Blenderized diets have been widely adopted as nutritional support, particularly for patients receiving formulae via an enteral route. Although the viscosity of thickened formulae is a determinant of adverse events, no study has examined the viscosity of blenderized diets. Aim: To examine the viscosity and temperature of four types of blenderized diet. Methods: Four types of rice porridge were prepared: rice porridge (RP) (Method 1); rice porridge with 0.5% alpha-amylase (RPA) (Method 2); rice porridge with 0.5% alpha-amylase and 0.5% thickener (RPAT) (Method 3); and rice porridge with 0.5% alpha-amylase and 0.5% thickener frozen overnight and defrosted (RPATFD) (Method 4). The viscosity and temperature of these four types of blenderized diet were measured for 30 minutes with a B-type viscometer. Results: The viscosity of blenderized diets over 30 minutes increased with decreasing temperature with Methods 1, 3, and 4. With Method 2, viscosity at 5 minutes was significantly lower than that with Method 1 (p < 0.05). Moreover, unlike the other three methods, viscosity with Method 2 decreased significantly over the 30 minutes (p < 0.05). This phenomenon might have been related to the activation of added amylase. Viscosity during the 30 minutes was within the range of 3,500-10,000 mPa.s, which is reported acceptable in clinical settings. Overnight freezing and defrost of the blenderized diet in Method 4 appeared to stably maintain the viscosity within the likely acceptable range achieved with Method 3. Conclusion: The addition of 0.5% thickener with 0.5% alphaamylase, either alone or followed by overnight freezing followed by defrosting, appeared to stably maintain the viscosity of a blenderized diet within the range likely acceptable in clinical settings. These findings might aid in the development of clinically usable blenderized diets.