Commonly used lactose assays [enzymatic spectrophotometric absorbance (EZA) and HPLC] for dairy ingredients are relatively expensive and time consuming. A blood glucose meter (BGM)-based method has successfully been documented as a rapid lactose assay in milk. However, the BGM-based method has not been evaluated in dairy ingredients. The objective of this study was to evaluate the BGM-based lactose analysis method in whey-derived (WD) and skim milk-derived (SMD) ingredients. The study was carried out in 4 phases. In phase 1, the effect of pH and lactose concentrations on the BGM reading was investigated using a factorial design with 2 factors: pH (6.02–7.50) and lactose (0.2 or 0.4%). We found that BGM readings were significantly affected by lower pH values at both lactose levels. In phase 2, the effect of total solids and ingredient type was investigated using a factorial design with 2 factors: ingredient type (WD or SMD) and total solids (0–8%). It was observed that the BGM reading was significantly affected by ingredient type and total solids. Phase 3 involved developing a linear relationship between the BGM reading and the EZA reference method to ascertain the accuracy of the proposed BGM method. Different ingredient types (WD or SMD) and non-lactose solids (0.5–27%) model ingredient dilutions prepared over a range of lactose contents (0.08–0.62%) were measured using the BGM and EZA methods. The average absolute percentage bias difference between the BGM method and EZA reference method results for these model dilutions was found to be between 2.2 and 7.3%. In phase 4, 15 samples procured from commercial sources ranging from 0.01 to 81.9% lactose were evaluated using the BGM method and EZA reference method. The average absolute percentage bias difference for lactose results between the 2 methods ranged from 3.6 to 5.0% and 5.3 to 9.7% for well-performing and poorly performing meters, respectively. Overall, the BGM method is a promising tool for rapid and low-cost analysis of lactose in both high-lactose and low-lactose dairy ingredients.
Bibliographical noteFunding Information:
This project was conducted under Kansas State Research and Extension contribution number 20-056-J. This work was partially supported by the USDA National Institute of Food and Agriculture (Washington, DC) Hatch project 1014344. We thank Midwest Dairy Foods Research Center (St. Paul, MN) for their partial financial support. We also thank Agropur Ingredients (Appleton, WI) for their support. Kansas State University (Manhattan) neither endorses nor takes responsibility for any products, goods, or services offered by outside vendors. The authors have not stated any conflicts of interest.
© 2020 American Dairy Science Association
Copyright 2020 Elsevier B.V., All rights reserved.
- blood glucose meter
- dairy ingredient
- rapid method
PubMed: MeSH publication types
- Evaluation Study
- Journal Article