Location: Methods and Application of Food Composition Laboratory
2023 Annual Report
Objectives
Objective 1. Determine the impact of industrial packaging methods (canning, freezing and drying) on the nutrients and bioactive compounds in fresh fruits and vegetables.
Objective 2. Validate a software program based on mathematical optimization techniques for estimating nutrient contents of commercial multi-ingredient foods.
Objective 3. Determine the impact of dietary fiber methodology on fiber composition and intake estimates.
Approach
Objective 1. Industrial processing alters nutrients/bioactive compounds in fruits and vegetables. A 2-step, 2-year study for sample collection will be conducted. Consulting USDA plant scientists/other collaborators, multiple same-cultivar ripe samples will be collected simultaneously from one. Samples will be analyzed for vitamins, fiber, minerals, polyphenols, and metabolomics (baseline). Portions will be transported and stored to emulate typical commercial storage conditions; nutrients/polyphenols will be conducted in stored raw samples every 3 days until they decay. Shipping practices for samples will be simulated through collaborations with processing plants near harvest locations, emulating agricultural and industrial practices. Analyses at 0, 14, 35, 70, 120, 180 and 360 days post processing, and analysis in validated commercial laboratories, using AOAC methods, polyphenolic compounds analysis by ARS/academic collaborators will address the impact of processing.
Objective 2. Linear programming software for estimating missing nutrient values in commercially processed foods (using label values, ingredient lists) requires improved automation and analytical ingredient data. Food types (e.g., baked products) and nutrients will be identified, program functionality improvements completed, and tests, where ingredient proportions and nutrient values are known, will allow determination of estimation accuracy. The Virginia Tech (VT) Food Analysis Laboratory Control Center will prepare foods and QC materials for analysis; food manufacturers will be consulted on ingredient proportions, and an equivalence study of the estimates will be conducted to determine classes of nutrients and food types where the estimated and analytical values are similar, i.e. within ± 20%. Program validation will ensue to assess which nutrients to include.
Objective 3. The McCleary method (MCF) is a more complete determination of dietary fiber (DF) content in foods compared to the enzymatic-gravimetric (EGF) method, enabling better intake estimates. Select high-fiber foods and frequently consumed, fiber-containing foods will be analyzed by EGF (985.29) and MCF (2011.25) methods at a USDA-qualified commercial analytical lab. Foods with isolated or synthetic non-digestible carbohydrates may be analyzed. EGF (AOAC 985.29; total DF) and EGF (AOAC 991.43; soluble and insoluble DF), and MCF (AOAC 2009.01 and 2011.25 (fractions) will be studied and summed. Sumswill determine the food types where the fiber method used does not make a difference for measuring total DF. This allowsbetter understanding of the effect of fiber methodologies for selecting the appropriate analytical method for specific foods.
Progress Report
Objective 1. Determine the impact of industrial packaging methods (canning, freezing and drying) on the nutrients and bioactive compounds in fresh fruits and vegetables. Analyses of free and bound carotenoids, different fractions of carbohydrates, minerals and phenolic acids (free, free conjugate and bound forms) were completed on ten different sweet corn samples to investigate the effects of post-harvesting, cooking and industrial processing. Two manuscripts were submitted to American Chemical Society Food Science and Technology, one was published and the second, accepted; two manuscripts are currently under preparation on carbohydrates and phenolic acids. All unprocessed and processed sweet corn samples were sent to the collaborator at University of California Davis (UC Davis for multi-glycomic analysis; the results suggested that, cooking and processing changes the amounts of different carbohydrates and alters the structures (including monosaccharide composition and glycosidic linkage of polysaccharides). To link the changes in nutrients and bioactive compounds after food processing to the possible alterations of digestion, an in vitro static digestion model INFOGEST was utilized to study the effects of food processing on the digestion and bio-accessibility of carotenoids and carbohydrates in sweet corn. Another study to investigate the effects of post-harvesting, cooking (steaming and boiling) and industrial processing (freezing) on nutrients and bioactive compounds in spinach was completed. Two major varieties (savoy and flat-leafed) of spinach are being analyzed for carotenoids, vitamins and flavonoids.
Objective 2. Validate a software program based on mathematical optimization techniques for estimating nutrient contents of multi-ingredient foods. IngID Thesaurus, an application for systematic reporting of ingredients used in commercially packaged foods, was drafted, and sent for external peer review, to be later published on the Methods and Application of Food Composition Laboratory (MAFCL) website. It contains ~26,000 parsed ingredient terms, that have been assigned ~3,000 PDs, categorized in a taxonomic hierarchy of 16 food groups and is the first time makes publicly available a tool that can potentially help reduce pre-processing and data clean-up for the study of ingredients as listed on labels of commercially packaged foods. Due for release in 2023.
Objective 3. Determine the impact of dietary fiber methodology on fiber composition and intake estimates. High carbohydrate foods were studied to determine the impact of dietary fiber methods and changes in the distribution of carbohydrate fractions during storage, senescence, and cooking, e.g., corn. Methods were expanded to include measurement of dietary fiber (enzymatic gravimetric AOAC 991.43), McCleary fiber (AOAC 2009.01, 2011.25), starch (digestible, residual, and retrograde, after cooking/cooling/reheating), and oligosaccharides; data were included in Food Data Central (FDC) Foundation Foods. We compared total dietary fiber (TDF), insoluble dietary fiber (IDF), and soluble dietary fiber (SDF) content in food substrates using an Automated Ankom Fiber Analyzer, the fractions determined using gravimetric methods AOAC 2017.16 and AOAC 991.43; they were further analyzed with rapid-throughput LC-MS to determine the structural composition of soluble/insoluble fractions at the total monosaccharide, glycosidic linkage, and free saccharide levels. In collaboration with the University of California, Davis, we are optimizing methods for fiber analysis using different food matrices. The Beltsville Human Nutrition Center (BHNRC) Carbohydrate Committee, the Carbohydrate Committee of Institute for the Advancement of Food and Nutrition Sciences, the Cereal Grains Association and the Nutrition Research Coordinating Committee National Institutes of Health contribute to the research; MAFCL scientists. Review of external carbohydrate data/datasets are being reviewed for linking and/or inclusion in FDC.
Additional Research Human Breast Milk Composition. MAFCL co-leads the Human Milk Composition Initiative (HMCI), a joint undertaking by federal U.S. and Canada agencies to articulate human milk-related data needs relevant to federal programs, policies, and regulations. A scoping review to identify studies that meet the inclusion criteria for developing new human milk composition estimates was submitted to the journal Advances in Nutrition, as was a commentary from HMCI leads.
Purines: A “western” diet and lifestyle along with the obesity epidemic are often associated with increased incidence of gout, a serious form of arthritis caused by high blood levels of uric acid; a high purine diet and other factors can raise uric acid levels. Work continues generating new analytical USDA data in foods and dietary supplements to support this research. MAFCL developed/released the USDA and ODS-NIH Database for Purine Content of Foods, version 1, on four key purine bases and total purines in foods, and to identify data gaps. It focuses on over 370 protein-rich foods and 15 alcoholic beverages from 14 published sources in North America and worldwide. Purine content varied for the same food in different studies, possibly due to natural variability in foods, different sampling plans, sample handling, and laboratory methods. These data will be expanded as our collaborative analyses with the Univ. of Florida for foods and dietary supplements are released in subsequent updates.
Nitrates and Nitrites: The paradox of dietary nitrates as potentially beneficial to cardiovascular and gastrointestinal immune function and adversely affecting specific physiological conditions, suggests need for research. Data on the nitrate/nitrite content of U.S. foods and dietary supplements are sparse; more data are needed to determine estimates for mean content and variability across U.S. products and population intakes. This dataset was developed by USDA and collaborators to provide data and to identify data gaps. Data were obtained from the analysis of foods using ozone chemiluminescence at the University of Oklahoma and from multiple U.S. published studies; values for 300 foods and beverages and 13 dietary supplements are included. It serves as a baseline for identifying additional products - foods and supplements containing substantial and/or variable amounts of nitrate/nitrite for which expanded sample sizes are needed. Researchers, nutritionists, and academia benefit as they develop recommendations for healthy diets and as they design research studies.
Dietary bioactive compounds and Special Interest Database. A paper that summarized current knowledge and discuss challenges for development of a dietary GSL database for U.S. foods was published in Current Developments in Nutrition. Results suggested that currently available U.S. data are insufficient to develop a valid GSL database.
Dietary Supplements. In the U.S., calcium ± vitamin D DS are used to improve status for under-consumed nutrients of public health concern. The efficacy of calcium DS relates to the nutrient amounts and proper release from dosage forms. The goals of this nationally representative study were to: measure calcium, vitamin D, other minerals; compare to labels/create calculators converting label amounts into predicted amounts; survey the current state of dosage form performance quality of calcium and vitamin D DS with disintegration/dissolution U.S. Pharmacopeia (USP) tests; and assess the impact of health claim regulations on dietary supplement quality. In addition, release 5 of the Dietary Supplement Ingredient Database, in collaboration with the NIH Office of Dietary Supplements is being developed for release later this year.
Nationally representative adult calcium dietary supplements (DS): nutrient strength, health claims and performance quality. Scientists at USDA ARS in Beltsville, Maryland, collaboratively with scientists at Office of Dietary Supplements at NIH, Bethesda, Maryland, tested over 100 calcium and calcium + vitamin D DS for their nutrient content. Expert laboratories analyzed 2-3 lots of 102 adult DS (calcium as the primary ingredient at =80 mg/serving), comparing with labels and Recommended Dietary Allowances (RDA). To pass in vitro tests (USP monographs), dosage units must disintegrate within 30 min and release =75% of labeled calcium amount within 30 or 60 min, depending on dosage form and product composition. All ingredients showed mean values greater than label claims. For calcium (n=102) and magnesium (n=50), the percent differences from label were 8.05±6.69 and 9.25±10.8 (mean±SD), respectively. For vitamin D, percent differences averaged 27.1% above labels (SD: 26.5; n=83). Only 53.2% of adult calcium and vitamin D DS passed dissolution tests; 33 products had a claim for reducing osteoporosis risk, but only 60% passed dissolution testing. DS with similar %RDAs failed or passed dissolution similarly. This is a concern for ordinary consumers and patients in clinical practice because micronutrients in failed products might not be available for absorption and utilization. A widespread view that all DS do not require obligatory testing using the United States Pharmacopeia (USP) standards must be modified: this research underscores DS with certain FDA approved health claims must meet dissolution and disintegration standards set by applicable USP monographs, like over-the-counter and prescription (Rx) drugs. The performance quality research of adult calcium DS has concluded.
Human milk composition and related data for national health and nutrition monitoring. In a paper in the Journal of Advanced in Nutrition, researchers at Beltsville, Maryland, along with other U.S. and Canada scientists developed a framework for collection and reporting human milk composition data for national health and nutrition monitoring and programmatic needs, including a vision for Human Milk Composition Repository.
Accomplishments
1. Carbohydrate research (analytical methods and carbohydrate fractions). The results showed that for oats, both Association of Official Analytical Collaboration (AOAC) methods gave similar results. The insoluble fiber was found to be comprised of linkages corresponding to ß-glucan, arabinoxylan, xyloglucan, and mannan, while soluble fiber was found to be mostly ß-glucan, with small amounts of arabinogalactan. However, for raw potato starch, each AOAC method gave markedly different results in the soluble fiber fractions. These observed differences are attributable to the resistant starch content of potato starch and the different starch digestion conditions used in each method This aligns with similar assessments made on harvested sweet corn subjected to processing (canning, freezing, cooking); changes in carbohydrate fractions were measured with different treatments and heat applications. Structural changes were shown, for the first time, with processing; however, in most cases, the total carbohydrates did not change.
2. Using ingredient statements for study of ingredients in commercial packaged foods. There is general lack of information in scientific literature and food composition databases on the ingredients used in commercial packaged foods. Researchers at Beltsville, Maryland, published a newly developed IngID system for determining the distribution and co-occurrence of ingredients used in baked products and tested the potential of IngID to answer research questions such as types of flours, fats, sweeteners, additives, etc. IngID enables characterization of what is in the foods we eat in a systematic manner, in dimensions other than the traditional nutrient profiles.
3. Human milk composition and related data for national health and nutrition monitoring. Understanding of child exposures through human milk remains out of reach due to lack of current and representative data on its composition and intake volume. Researchers at Beltsville, Maryland, along with 18 other scientists from various public health agencies in the U.S. and Canada developed a framework for collection and reporting of human milk composition data for national health and nutrition monitoring and programmatic needs, including a shared vision for a publicly available Human Milk Composition Data Repository (HMCD-R) to include essential meta-data associated with human milk composition. HMCD-R could facilitate understanding the complexity and variability of human milk composition, provide crucial data for assessment of infant and maternal nutritional needs, and inform public health policies, food and nutrition programs, and clinical practice guidelines.
4. Nationally representative adult calcium dietary supplements (DS): nutrient strength, health claims and performance quality. Scientists at USDA ARS in Beltsville, Maryland, collaboratively with scientists at Office of Dietary Supplements at NIH, Bethesda, Maryland, tested over 100 calcium and calcium + vitamin D DS for their nutrient content. All ingredients in these DS showed mean content greater than label claims. For calcium (n=102) and magnesium (n=50), the mean percent differences from label were 8.05 ± 6.69 (SD) and 9.25±10.8, respectively. For vitamin D in these DS, percent differences from labels were higher, averaging 27.1% above labels (SD: 26.5; n=83). The measured percentage differences from the labels will be used to create calculators to improve the precision of nutrient intake calculations for the U.S. population for these under-consumed nutrients of public health concern. Although vitamin D and minerals in adult calcium DS may help to close nutrient gaps, 53.2% of tested DS, including those with the osteoporosis health claim failed to meet the USP dissolution standards, even though DS with this health claim are required by the Food and Drug Administration to meet these standards. This is a concern for ordinary consumers and patients in clinical practice because micronutrients in failed products might not be available for absorption and utilization. A widespread view that all DS do not require obligatory testing using the United States Pharmacopeia (USP) standards must be modified: DS with certain FDA approved health claims must meet dissolution and disintegration standards set by applicable USP monographs, like over-the-counter and prescription (Rx) drugs.
Review Publications
Gao, B., Zhu, L., Liu, Z., Li, Y., He, X., Wu, X., Pehrsson, P.R., Sun, J., Xie, Z., Slavin, M., Yu, L. 2023. Chemical composition of honeysuckle (Lonicerae japonicae) extracts and their potential in inhibiting the SARS-CoV-2 spike protein and ACE2 binding, suppressing ACE2, and scavenging radicals. Journal of Agricultural and Food Chemistry. 71(15):6133-6143. https://doi.org/10.1021/acs.jafc.3c00584.
Xie, Z., Li, Y., Liu, Z., Zeng, M., Moore, J., Gao, B., Wu, X., Sun, J., Wang, T.T., Pehrsson, P.R., He, X., Yu, L. 2023. Chemical characterization of cinnamon (Cinnamomum verum J. Presl) extracts and their capacities in weakening SARS-CoV-2 spike protein binding to ACE2, inhibiting ACE2 and scavenging free radicals. Journal of Agricultural and Food Chemistry. 71:4890-4900. https://doi.org/10.1021/acs.jafc.3c00285.
Ahuja, J.K., Li, Y., Wu, X., Pehrsson, P.R., Chakrabarti, S., Brooks, S.P., Bondy, G.S., MacFarlane, A.J., Weiler, H.A., Cheung, W., Verreault, M., Hayward, D., Fisher, M.M., Borghese, M.M., Hines, E., Ahluwalia, N., Vargas, A.J., Arteaga, S., Lombo, T. 2022. Human milk composition and related data for national health and nutrition monitoring and related research. Advances in Nutrition. 13(6):2098-2114. https://doi.org/10.1093/advances/nmac099.
Ahuja, J.K., Li, Y., Quynhanh, N., Pehrsson, P.R. 2022. Characterizing ingredients in commercially packaged baked products sold in the U.S.: an application of IngID. Journal of Food Composition and Analysis. 114:104830. https://doi.org/10.1016/j.jfca.2022.104830.
Whent, M.M., Huang, J., Childs, H., Slavin, M., Harrison, D.J., Novotny Dura, J., Yu, L., Pehrsson, P.R., Wu, X. 2023. Evaluation of postharvest handling and domestic cooking on carotenoids in sweet corn. Journal of Agricultural and Food Chemistry. 71:6133-6143. https://doi.org/10.1021/acs.jafc.3c00584.
Bacalzo,.P., Couture, G., Ye, C., Luthria, D.L., Phillips, K.M., Fukagawa, N.K., Lebrilla, C.B., Tareq, F.S., Harnly, J.M., Pehrsson, P.R., McKillop, K.A. 2022. Multi-glycomic characterization of fiber from AOAC methods defines the carbohydrate structures. Journal of Agricultural and Food Chemistry. 70(45):14559-14570. https://doi.org/10.1021/acs.jafc.2c06191.
