Research Project: New Technologies and Methodologies for Increasing Quality, Marketability and Value of Food Products and Byproducts

Location: Healthy Processed Foods Research

2023 Annual Report

Objectives
Objective 1: Enable commercially-viable new technologies to detect and mitigate contaminants or defective products from food streams. • Sub-objective 1A: Investigate x-ray as an alternative to gamma for food irradiation. • Sub-objective 1B: Detect and mitigate fruit fly infestation in olives. • Sub-objective 1C: Develop real-time non-destructive analysis of vanilla for adulteration. Objective 2: Utilize advanced analytical and sensory methods to detect, identify, and quantify desirable and undesirable odors and taste defects in raw and processed foods. • Sub-objective 2A: Identify compounds in raw and processed specialty crops including peas and grapes that impact flavor and taste. Identify precursors (and eventually pathways) of these compounds and study flavor variation in different varieties. • Sub-objective 2B: Evaluate almond hulls for use in natural sweeteners or as a supplement to bee diets. Investigate the effects of almond hull phenolics on the acceptability of almond hull sugars in bee diets. Objective 3: Develop commercially-marketable novel, value-added cereal-based healthy, tasty food products. • Sub-objective 3A: Utilize oil seed (canola, sunflower and cotton) waste products to produce gluten-free, high protein flatbreads, snacks and pasta and evaluate for consumer acceptance.

Approach
1A: Baby spinach will be used to see if x-ray can replace gamma for food irradiation. The spinach will be inoculated with Shiga toxin-producing E. coli (STEC) strains and irradiated under x-ray and gamma irradiation. Pathogen populations will be monitored by plate count for differences between treatments of dose vs. population reduction. Should spinach not tolerate irradiation well a different commodity will be used. Other pathogens could also be studied, including Salmonella and Listeria. 1B: X-ray imaging and NIR spectroscopy will be evaluated for detection of olives infested with fruit flies. An olive fly colony will be established on-site for generation of infested samples. Film x-ray images will be acquired and digitized, and NIR spectra acquired. Chemometrics, neural network, discriminant analysis, and k nearest neighbor algorithms will be employed. 1C: NIR spectroscopy will be used to quantify coumarin and ethyl vanillin adulterations in vanilla extracts. Vanilla samples will be diluted using CMR, and NIR spectra obtained. Calibration equations for quantitative prediction will be developed. Collaborators will provide samples of vanilla extract processed using the method of green drying which bypasses the traditional curing process. NIR spectra will be acquired and calibrations developed to differentiate between vanilla extract processed under green drying vs. the traditional manner. Should the high ethanol and water concentrations in vanilla extract and concentrate make it impossible to obtain reliable calibrations, evaporation techniques will be developed to remove the ethanol and water and the remaining residue will be used to acquire spectra. 2A: Flavor compounds in peas and grapes will be quantified, precursors identified, and flavor variation studied between varieties. Pea protein will be produced from pea flour under spray drying and drum drying with different time and temperature conditions, and Grosch’s method of flavor analysis will be applied along with identification and quantification of saponins in pea flour and protein. GC-MS spectra will be matched to those in established libraries to identify food constituents. Aroma models will be compared with the food products by sensory panels. 2B: Sugars will be eluted from almond hulls using water and their composition determined by HPLC. Anthocyanins, flavonols, and hydroxycinnamates will be identified by comparison of retention times and UV/Vis spectra of unknown peaks with those of authentic standards. Weight and total phenolic content will be determined for each extract. Bee diet samples will be developed using a 25 °Brix solution of almond hull extract. 3A: Canola, sunflower and cotton seeds will be used to produce gluten-free products with high protein content and consumer acceptance. Various formulations of gluten-free cereal flours, seed meal vegetables and “condiments” will be used to produce pasta, snacks, and flatbread and presented to sensory panels. Proximate analysis will be applied to measure protein, fat, ash and moisture at each stage of processing. Those products that form crust (flatbreads and snacks) will be evaluated for acrylamide levels using LC-MS.

Progress Report
In support of Sub-objective 1A, a new x-ray irradiator has been developed with a configuration that allows easier irradiation of flat samples such as lettuce and spinach. Irradiation experiments are on hold due to loss of access to a suitable gamma irradiator. In support of Sub-objective 1B, near-infrared (NIR) spectra of infested versus non-infested olives have been collected and standard chemometric techniques indicate good success at detecting late-stage infestations. X-ray imaging is delayed due to loss of access to an x-ray film developer, and digital alternatives are being explored. In support of Sub-objective 1C, NIR spectra of ethyl vanillin (EVA) spiked vanilla extract samples have been generated and applied detection algorithms indicate excellent ability to identify and quantify adulteration. In support of Sub-objective 2A, a detailed literature review of aroma constituents in pea protein was conducted. The aroma of pea protein was studied using solid-phase microextraction (SPME) coupled with analysis by gas chromatography-mass spectrometry (GC-MS). In support of Sub-objective 2B, various sample preparation methods and high-performance liquid chromatography (HPLC) columns and mobile phase compositions were investigated to determine the optimum methods for extraction and separation of phenolic constituents in almond hull extracts. These methods were studied to determine the efficacy of treatments designed to reduce the amounts of phenolics in almond hulls extracts. Phenolics reduce the feeding behavior of bees and their concentration must be reduced for product acceptance. In support of Sub-objective 3A, proximate analysis of millet-based flatbread ingredients has been competed, sensory panels have been conducted, and a manuscript was prepared for submission. Colored corn-based flatbreads containing healthy algae (Eclonia Cava) have been formulated and proximate analysis of ingredients was completed. A manuscript is under preparation.

Accomplishments
1. New HPLC method for ergothioneine analysis. Ergothioneine (Ergo) is a potent anti-inflammatory and antioxidant amino acid well-known to be highly bioavailable through mushroom consumption. However, outside of mushrooms, limited knowledge exists regarding Ergo content in foods. It has been postulated that soil-borne fungi or bacteria produce Ergo that is passed on to plants through their roots, suggesting that other plants beside mushrooms could have higher Ergo concentrations. ARS researchers in Albany, California, have developed a rapid, reliable, accurate and sensitive high-performance liquid chromatography method for the identification and quantification of Ergo which will facilitate Ergo analysis of a wide range of food products. Furthermore, this new analysis method provides the means to quantify the effects of processing on Ergo content of processed foods. This technology impacts food growers, processors, and consumers by providing critical information regarding nutritional content and health benefits of food products that is currently lacking.

2. Colored corn-based flatbreads containing healthy algae (Eclonia Cava). Ecklonia cava, an algae rich in vitamins, minerals, protein, fiber, and other beneficial plant chemicals, has a long history of use in traditional medicine to treat goiters, hemorrhoids, urinary diseases, constipation, stomach ailments, and many other disorders. ARS researchers in Albany, California, have developed both corn and wheat-based flatbreads incorporating Ecklonia Cava as a basic ingredient. Proximate analysis of the flatbreads indicates higher mineral, protein, and fiber content versus their traditional counterparts. The developed methodology provides the means to incorporate a highly beneficial and nutritious ingredient into traditional foods. These novel food products impact food producers and consumers by providing healthy alternatives to traditional foods, with subsequent impact in terms of obesity and disease prevention.

Review Publications
Bilbao-Sainz, C., Chiou, B., Takeoka, G.R., Williams, T.G., Wood, D.F., Powell-Palm, M., Rubinsky, B., Wu, V.C., McHugh, T.H. 2022. Isochoric freezing and isochoric supercooling as innovative postharvest technologies for pomegranate preservation. Postharvest Biology and Technology. 194. Article 112072. https://doi.org/10.1016/j.postharvbio.2022.112072.
Zhang, Y., Bhardwaj, S.R., Vilches, A.M., Breksa III, A.P., Lyu, S., Chinthrajah, S., Nadeau, K., Jin, T. 2022. IgE binding epitope mapping with TL1A tagged peptides. Molecular Immunology. 153:194-199. https://doi.org/10.1016/j.molimm.2022.12.001.
Bilbao-Sainz, C., Chiou, B., Takeoka, G.R., Williams, T.G., Wood, D.F., Powell-Palm, M., Rubinsky, B., McHugh, T.H. 2022. Novel isochoric cold storage with isochoric impregnation to improve postharvest quality of sweet cherry. ACS Food Science and Technology. 2(10):1558-1564. https://doi.org/10.1021/acsfoodscitech.2c00194.