Using NMR Spectroscopy to Characterize Debranched Waxy Rice Starches Used in Ice Cream Formulations

Debranched waxy rice (DBWR) starches can serve as a fat substitute in ice cream formulations, and nuclear magnetic resonance (NMR) spectroscopy has helped to show this, recent research published in Food Bioscience finds (1).

The ice cream industry has a $11.4 billion impact on the U.S. economy and generates $1.9 billion in direct wages (2). According to the International Dairy Foods Association, many ice cream manufacturers have been in business for decades, and most are small, family-owned businesses (2).

Strawberry, vanilla, chocolate ice cream with waffle cone on marble stone backgrounds | Image Credit: © ahirao - stock.adobe.com

As a dessert, ice cream is not known as a health food. As a high source of fat, ice cream is one of the unhealthiest foods for consumers, despite its addictive rich taste and texture. The fat content in ice cream gives this dessert the creamy texture and mouthfeel that consumers enjoy (1). However, the growing awareness of the health risks associated with excessive fat intake has driven demand for low-fat ice cream options. Unfortunately, reducing fat content can compromise both the taste and consistency of the product (1). Manufacturers often struggle to maintain the smooth texture and rich flavor that ice cream lovers expect when lowering fat levels (1).

Alternative forms of ice cream have been created, such as frozen yogurt. However, the consensus is that frozen yogurt, while a decent substitute, does not taste as great as regular ice cream. A recent study led by Yan Hong from Jiangnan University and the Jiaxing Institute of Future Food in China proposed a new way to create high-quality low-fat ice cream that retains its rich taste and texture. Hong and his group, understanding that traditional fat substitutes do not mimic the properties of fat well, showed how DBWR starch could be an effective fat substitute in ice cream formulations and serve as a healthier option for consumers who seek reduced-fat alternatives without sacrificing quality (1).

In their study, the researchers found that the debranching process alters the molecular structure of the starch, reducing its molecular weight from 17.03 × 10⁶ g/mol to 9.18 × 10⁴ g/mol. This change increases the short-chain amylose content and the dextrose equivalence value, both of which are crucial to enhancing the texture and stability of the ice cream mixtures (1).

One of the most important findings was that as the degree of debranching increased, the particle size of the ice cream mixture decreased, stabilizing after four hours of debranching at a particle size of 1.356 ± 0.364 μm (1). This smaller particle size contributed to a more stable emulsion, improving the ice cream’s overall texture and consistency. Furthermore, the mixture demonstrated a high Zeta potential, exceeding −30 mV, which is associated with better emulsion stability, crucial for creating a smooth, uniform product (1).

Another aspect to this study was the role proton NMR spectroscopy played in the pullulanase treatment on the branching density of DBWR (1). The results indicated that as debranching time increases, the DBWR dextrose equivalent (DE) values rise (1). This phenomenon occurs because amylases break down starch into reducing substances, and a longer debranching time leads to more degradation, producing more reducing substances and higher DE values (1).

The research highlighted that DBWR starches with two and four hours of debranching (DBWR-2 and DBWR-4) provided the best results. These formulations offered sensory properties that closely resembled medium-fat ice cream, providing a smooth, rich mouthfeel and flavor (1). In terms of consistency, the low-fat ice creams with DBWR-2 and DBWR-4 substitutions performed nearly identically to their full-fat counterparts.

Although other starches have been tested as fat substitutes in the past, the study found that DBWR can be a good substitute because of its small particle size and concentrated molecular weight. These properties give it an edge over more commonly used starches, providing a more stable, uniform, and high-quality fat substitute (1).

As the demand for healthier, lower-fat options continues to grow, the ability to produce a low-fat ice cream that does not compromise on quality could revolutionize the market. DBWR starch offers a practical, scalable solution that could be easily incorporated into existing ice cream production processes.

References

1. Jin, Y.; Gu, Z.; Cheng, L.; et al. Physicochemical Characterization of Debranched Waxy Rice Starches and their Effect on the Quality of Low-fat Ice Cream Mixtures. Food Biosci. 2024, 57, 103485. DOI: 10.1016/j.fbio.2023.103485
2. International Dairy Foods Association, Ice Cream Sales & Trends. IDFA.org. Available at: https://www.idfa.org/ice-cream-sales-trends (accessed 2024-09-17).