Progress report for ONE20-362
Project Information
The objective of this project is to identify successful flint corn varieties, management practices, and key physical and sensory characteristics of flint cornmeal and products, to better understand farmer, food manufacturer, and consumer needs to expand the flint corn market in the Northeast. Varieties will be evaluated for agronomic characteristics including vigor, disease and pest resistance, standability, and grain yield. We will also investigate flint corn populations to optimize yield and quality. Each variety will be assessed for milling quality including kernel size uniformity, proneness to cracked kernels, proportion of horny endosperm to soft endosperm, and amount of large bran flakes present in the cornmeal. Cornmeal from each variety will be evaluated for sensory quality including aroma and flavor. The evaluation will be made by a panel of trained tasters using established descriptive sensory analysis methods that allow us to objectively define and compare the aroma and flavor of the samples. Select flint corn varieties will be used to prepare consumer products, such as tortillas, which will be evaluated for characteristics that support consumer acceptance and market success. The data generated by this sensory analysis on finished products will be correlated against the sensory data generated on the cornmeal samples, as well as the agronomic information, to meet the overall objective of identifying successful flint corn varieties that meet the needs of farmers, food manufacturers, and consumers in this emerging market. Information will be shared widely with farmers and end-users through print materials, video, online resources, and outreach events.
This project seeks to evaluate flint corn variety performance and suitability to this region’s climate and farming systems and their potential to be used by food and beverage manufacturers to produce successful consumer products.
The questions we will answer are:
- Which flint corn varieties are best suited for growing in the Northeast?
- Are the production practices (i.e. populations) for flint corn different than dent corn?
- What consumer food products are each flint corn variety suitable for producing?
- Which flint corn varieties result in food products that best meet consumer aroma and flavor preferences?
- What metrics can be used at the farm-level to predict processing performance and suitability in addition to sensory quality of end products?
Answering these key questions will help local farmers employ successful production practices and select flint corn varieties that are suitable for local processors. This will help develop strong relationships between local farmers and processors enhancing local food system resiliency. It will also provide insight into consumer preferences related to flint corn food products and will begin to determine characteristics of seed quality required by processors require to make products that meet these consumer preferences to ensure successful markets.
In 2019 there were almost 90 million acres of corn planted in the US (USDA NASS). This acreage is primarily dedicated to growing dent corn for feeding livestock. However, it is also used for food ingredients and products such as corn starches, corn syrups, tortillas, and tortilla chips. There are other types of corn, such as flint, that we also use in food products. It gets its name from the hard, glassy, and flint-like nature of its kernels and was originally cultivated by Native Americans prior to colonization. Although flint corn has been grown in the Northeastern US for centuries, its use outside of small specialty and cultural markets has been limited. There is growing interest from food manufacturers to make products such as tortillas and tortilla chips using flint corn. However, these companies lack critical information on the suitability of flint corn varieties, and seed quality parameters, to successfully make these products. In addition, they lack an understanding of consumer preferences for the aroma, flavor, and texture characteristics of products made with flint corn. Lastly, they often lack needed access to locally grown, high quality flint corn. Farmers interested in growing flint corn for these companies lack much needed information on farming practices, and variety selection, and have limited access to the quantity of high-quality seed needed for commercial cultivation.
Therefore, there are a number of factors contributing to the limited use of flint corn in our region: 1) the majority of corn breeding has centered around dent corn which holds the largest market share in the US; 2) farmers and food companies lack information on growing flint corn and using it as an alternative to dent corn, or other grains, in products that meet consumer needs; and 3) farmers lack access to suitable flint corn seed and genetics for their region.
This project aims to evaluate and identify flint corn varieties that are suitable to the growing conditions in the Northeastern US, and that have the physical and sensory characteristics to successfully produce value-added corn products that meet the needs of consumers. We will meet the aims of this project by conducting flint corn variety trials with our farm partners to determine production practices and varieties that thrive in our climate to produce high quality yield and fit our agricultural systems and scale. We will work with a local food manufacturer to understand the challenges of using flint corn to make food products such as tortillas and define the quality parameters that indicate suitability of use for a flint corn variety. Finally, we will use a trained descriptive sensory panel to objectively measure the sensory characteristics of flint corn varieties, products made with them, and interpret the results relative to known consumer preferences. This research will increase the opportunities for growers to supply flint corn to food manufacturers, who will be able to produce food products that better meet the needs of consumers to expand the current market.
Cooperators
- (Researcher)
- - Technical Advisor (Educator and Researcher)
- (Researcher)
- - Producer
- - Producer
Research
The overall objective of our project is to use flint corn field trials and a sensory directed product development approach to expand the flint corn market in the Northeast, while sharing the approach and results to the benefit of other grain growers in the United States.
Which flint corn varieties are best suited for growing in the Northeast?
Flint Corn Variety Screening Trial
The availability of high-quality flint corn varieties in the northeast region is variable and relatively low compared to dent corns. After several years of trialing as many varieties as we could find, it became clear that many of the varieties that are available on the market are either poorly adapted to our region’s growing season, do not possess the agronomic characteristics needed in commercial production, or are too expensive for a commercially viable business. Therefore, we decided to broaden the scope of our varietal evaluations to screen flint corn germplasm for basic agronomic traits. Sixty flint corn accessions were obtained from the USDA National Plant Germplasm System. Approximately 100 seeds of each accession were seeded in three rows planted 30” apart in Alburgh, VT on 21-May 2021. Each accession was therefore planted at approximately 26,000 seeds ac-1. Each plot was evaluated for plant population, number of barren plants, plant height, ear height, lodging severity, ear disease severity, corn yield, and corn test weight when the corn reached black layer. For accessions for which there is sufficient material, samples will be processed in order to evaluate the sensory characteristics of the corn. This will help us to understand the potential culinary value of these accessions in hopes to identify those that have both agronomic and culinary potential.
Are the production practices (i.e. populations) for flint corn different than dent corn?
Impact of Seeding Rate on Heirloom Corn Yield
In 2021, two grain corn varieties, one flint and one heirloom dent, were each seeded at six different seeding rates at Borderview Research Farm in Alburgh, Vermont (Table 1). The trial design was a randomized complete block with split plots and four replications. Main plots were the varieties while sub-plots were seeding rates ranging from 20,000 to 30,000 seeds ac-1. Plots were evaluated for populations, lodging, grain yield, grain moisture, and grain test weight. The soil type at the Alburgh location is a Covington silty clay loam. The seedbed was prepared with a Pottinger TerraDisc. The previous crop was corn silage. Prior to planting, plots were fertilized with 19-19-19 at a rate 300 lbs ac-1 on 6-Apr. Plots were planted on 24-May with a 4-row cone planter with John Deere row units fitted with Almaco seed distribution units (Nevada, IA). Liquid starter fertilizer (9-18-9) was applied at planting at a rate of 5 gal ac-1. Plots were 20’ long and consisted of four rows of corn 30” apart. Populations were counted in each plot after emergence at prior to harvest. An application of Acuron was made on 4-Jun at a rate of 3 qt ac-1 to control weeds. On 7-Jul plots were top-dressed with 400 lbs ac-1 24-12-18.
Table 1. Treatment and trial management information.
Location |
Borderview Research Farm- Alburgh, VT |
Soil type |
Covington silty clay loam |
Previous crop |
Corn silage |
Row width (in) |
30 |
Plot size (ft) |
10 x 20 |
Varieties |
Cascade Ruby-Gold (flint type) Wapsie Valley (dent type) |
Seeding rates (seeds ac-1) |
20,000 22,000 24,000 26,000 28,000 30,000 |
Planting date |
24-May |
Tillage operations |
Pottinger TerraDisc |
Weed control |
3 qt. ac-1 Acuron 4-Jun |
Harvest dates |
8-Oct (Cascade Ruby-Gold) 5-Nov (Wapsie Valley) |
On 8-Oct and 5-Nov the Cascade Ruby Gold and Wapsie Valley plots were harvested respectively. Corn populations and the number of barren plants, plants that did not form an ear, were counted. Plots were also visually assessed for lodging severity on a scale from 0 (no lodging) to 5 (completely lodged). Corn was picked by hand and fed through an Almaco SPC50 plot combine. The corn from each plot was weighed and the moisture and test weight measured using a Dickey John Mini-GAC Plus moisture and test weight meter. Yield data and stand characteristics were analyzed using mixed model analysis using the mixed procedure of SAS (SAS Institute, 1999). Replications within trials were treated as random effects, and hybrids were treated as fixed. Hybrid mean comparisons were made using the Least Significant Difference (LSD) procedure when the F-test was considered significant (p<0.10).
What consumer food products are each flint corn variety suitable for producing?
Which flint corn varieties result in food products that best meet consumer aroma and flavor preferences?
Fall 2020: Preparation for the 2021 growing season
In addition to the identification of the corn varieties to be used in this project, the descriptive sensory analysis piece was kicked-off and cornmeal sample preparation and sensory method development for its evaluation was initiated. One of the aims of this project is to develop new and effective ways to prepare cornmeal samples on which objective descriptive sensory analysis can be conducted to generate data that can be successfully correlated with both practices at the farms and sensory performance of final products such as corn tortillas and chips. We plan to adapt the standard approach used by many large international food companies to conduct sensory screening on grains such as corn. Typically, a 10% aqueous solution of each cornmeal sample is produced and submitted for objective descriptive sensory analysis.
The timeline and task updates are as follows:
August 2020: Project kick-off and logistics planning
A virtual meeting was held with the UVM Extension Northwest Crops and Soils Program team and staff from the All Souls Tortilleria to discuss the award and review overall project activities and timing, including the fall 2020 and winter 2021 preparations for the 2021 growing season.
January - March 2021: Sensory Orientation and Training
Early in January 2021, we collected corn tortilla chip samples produced by All Souls Tortilleria in Burlington, Vermont, to use in a sensory orientation of the trained descriptive sensory analysis panel at the University of Vermont Extension. Due to Covid-19 restrictions, individual samples were distributed to the UVM Extension trained tasters, and representatives from All Souls Tortilleria, and a virtual sensory orientation taste session was facilitated by Roy Desrochers on January 8, 2021. Participants used standard sensory methods to assess the headspace aroma of each sample bag and then record both flavor and texture data.
A modification of the Flavor Profile Method (FPM) of Sensory Analysis called Total Intensity of Aroma (TIA) was used for the bag headspace aroma analysis. FPM and TIA are standard sensory methods well defined and accepted through the American Society for Testing and Materials (ASTM), specifically committee ASTM E-18 which develops standard sensory methods. (Reference: ASTM ML 13)
The flavor and texture of the samples was assessed using another modification of FPM call Profile Attribute Analysis (PAA) which is another standard ASTM method. These sensory methods will be used by the UVM Extension descriptive sensory analysis panel in the fall of 2021 to evaluate flint corn meal samples at the farm level, as well as flint corn tortillas and tortilla chips produced by All Souls Tortilleria using the trial flint corn samples.
In addition, a virtual hands-on flint and dent corn sensory demonstration was included as a component of the 2021 Northern Grain Growers Association Annual Conference.
November - December 2021: Harvest, Physical Testing, and Sensory Directed Product Development
The flint corn trials will be harvested in the fourth quarter of 2021. Prior to harvest, plots will be assessed for populations, number of ears fully formed, number of plants forming ears, lodging presence and severity, ear orientation and husk cover. Plots will be hand harvested and yield, average ear length and number of kernel rows will be recorded. A subsample of ears will be shelled, and harvest grain moisture and test weight measured using a Dickey-John Mini-GAC Plus meter. Ears from each variety were fully dried in a grain bin, shelled, and a subsample submitted to the UVM Cereal Grain Testing Lab for a basic corn nutrient analysis via NIR (Near Infrared Reflectance) procedures and Deoxynivalenol (DON) content.
In 2022, cornmeal samples will be prepared for each of the 3 flint corn varieties and assessed by the UVM Extension descriptive sensory analysis panel using the sample preparation and analysis methods developed in the first quarter of 2021. We will then select samples of flint corn from the variety trials, based on agronomic performance and DON concentrations, and deliver them to All Souls Tortilleria for processing into food products. The samples will be nixtamalized, a process of cooking in a hot water bath with culinary lime to remove the pericarp and alter the proteins to create a malleable dough. The trained panel will conduct descriptive sensory analysis on a small portion the whole kernel, nixtamalized corn, known as hominy. Remaining hominy will be wet milled into a masa dough and rolled into tortillas. The tortillas will be both baked into whole tortillas and cut and fried into tortilla chips. Objective descriptive sensory analysis will be conducted on both tortilla and tortilla chips samples. The trained sensory panel will also generate texture profiles for all the finished corn product samples. Aroma, flavor, and texture results for the end-products will be correlated with all other farming, flint corn variety, and flint corn sensory data, to connect these variables to end-product performance, which will be interpreted using the Flavor Leadership Criteria. (FLC) The FLC are a powerful set of sensory criteria, developed by ADL, to identify products with market leading potential. These criteria include early identifiable flavor, amplitude, mouthfeel, off-notes, and aftertaste.
Which flint corn varieties are best suited for growing in the Northeast?
Flint Corn Variety Screening Trial
At the time of the annual report, data from the screening trial had not been analyzed. A evaluation of the flint corn varieties will be completed and successful varieties selected for inclusion in the 2022 trial.
Are the production practices (i.e. populations) for flint corn different than dent corn?
Impact of Seeding Rate on Heirloom Corn Yield
Weather data was recorded with a Davis Instrument Vantage Pro2 weather station, equipped with a WeatherLink data logger at Borderview Research Farm in Alburgh, VT (Table 2). Temperatures were above normal in all months except for July which experienced temperatures more than four degrees below normal. Rainfall was below normal through August with September being approximately normal and October receiving more than two inches above normal. Overall, the region was classified as being in abnormally dry or moderate drought conditions for the majority of the season (Drought.gov). These conditions also brought more Growing Degree Days (GDDs) with a total of 2496 being accumulated through the growing season, 110 above the 30-year normal.
Table 2. Weather data for Alburgh, VT, 2021.
Alburgh, VT |
June |
July |
August |
September |
October |
Average temperature (°F) |
70.3 |
68.1 |
74.0 |
62.8 |
54.4 |
Departure from normal |
2.81 |
-4.31 |
3.25 |
0.14 |
4.07 |
|
|
|
|
|
|
Precipitation (inches) |
3.06 |
2.92 |
2.29 |
4.09 |
6.23 |
Departure from normal |
-1.20 |
-1.14 |
-1.25 |
0.42 |
2.40 |
|
|
|
|
|
|
Growing Degree Days (50-86°F) |
597 |
561 |
727 |
394 |
217 |
Departure from normal |
73 |
-134 |
85 |
7 |
79 |
Based on weather data from a Davis Instruments Vantage Pro2 with WeatherLink data logger.
Historical averages are for 30 years of NOAA data (1991-2020) from Burlington, VT.
Impact of Variety
The two varieties in the trial differed significantly in the proportion of plants that were barren and in lodging severity but performed statistically similarly in all other measures including yield (Table 3). The Cascade Ruby-Gold variety had approximately twice the number of barren plants compared to the Wapsie Valley, totaling over 1000 plants ac-1. This accounted for approximately 5% of Cascade Ruby-Gold plants. The two varieties, across all seeding rates, established an average of 20,274 plants ac-1 and did not differ statistically. In addition to barren plants, the Cascade Ruby-Gold variety experienced significantly higher lodging severity. While no lodging was observed in the Wapsie Valley plots, on average the Cascade Ruby-Gold plots had a lodging severity of 2.25 on a scale from 0-5. Lodging prior to harvest can leave ears vulnerable to damage from pests and rot while also increasing the potential for greater harvest losses as some lodged stalks may leave ears too low to combine easily. Despite this both varieties yielded well producing an average of 4569 lbs ac-1 or 81.6 bu ac-1 when adjusted to 13% moisture. The varieties did not differ in the moisture content at harvest or kernel test weight. Both varieties required additional drying to reduce kernel moisture to safe storage levels and had test weights below the industry standard for shell corn of 56 lbs bu-1. This was likely due to dry conditions throughout the season, especially during critical developmental stages including pollination and seed fill.
Table 3. Harvest characteristics of two specialty corn varieties, 2021.
Variety |
Populations |
Barren plants |
Lodging |
Harvest moisture |
Test weight |
Yield at 13% moisture |
|
plants ac-1 |
0-5 scale |
% |
lbs bu-1 |
lbs ac-1 |
bu ac-1 |
||
Cascade Ruby-Gold |
20564 |
1016 |
2.25 |
22.3 |
53.2 |
4776 |
85.3 |
Wapsie Valley |
19983 |
526 |
0.00 |
21.7 |
53.3 |
4341 |
77.5 |
Level of significance |
NS† |
**‡ |
***§ |
NS |
NS |
NS |
NS |
Trial mean |
20274 |
771 |
1.13 |
22.0 |
53.2 |
4569 |
81.6 |
†NS- not statistically significant
‡** 0.05 < p > 0.01
§***p < 0.0001
Impact of Seeding Rate
Seeding rate did not significantly impact yield, test weight, lodging, or the proportion of barren plants (Table 4). The highest yield was obtained at a seeding rate of 26,000 plants ac-1 but did not significantly differ from all other seeding rates including down to 20,000 plants ac-1 and up to 30,000 plants ac-1. This suggests that, for these two corn varieties, no additional yield benefit is gained from increasing seeding rates beyond 20,000 plants ac-1. Plant populations differed significantly which was intended. However, it is interesting to note the actual plant populations attained by each seeding rate. While seeding rates ranged from 20,000 to 30,000 plants ac-1, actual harvest populations ranged from 17,152 to 23,196 plants ac-1. While the actual populations attained in the trial followed the intended treatments on a relative basis, these data also suggest that these corn varieties may be even produce substantial yields when planted at rates less than 20,000 plants ac-1. Some of the discrepancy between the seeding rate and final plant population attained may have been due to the exceptionally dry conditions following planting and throughout the trial which likely impacted germination and establishment.
Table 4. Harvest characteristics of six seeding rates of grain corn, 2021.
Seeding rate |
Populations |
Barren plants |
Lodging |
Harvest moisture |
Test weight |
Yield at 13% moisture |
|
plants ac-1 |
plants ac-1 |
0-5 scale |
% |
lbs bu-1 |
lbs ac-1 |
bu ac-1 |
|
20,000 |
17152d† |
599 |
1.13 |
22.3ab |
53.3 |
5037 |
90.0 |
22,000 |
18785cd |
708 |
1.00 |
22.5b |
52.8 |
4814 |
86.0 |
24,000 |
19765c |
762 |
1.25 |
22.3ab |
52.5 |
4618 |
82.5 |
26,000 |
20637bc |
871 |
1.25 |
22.5ab |
54.6 |
5506 |
98.3 |
28,000 |
22107ab |
980 |
1.13 |
22.6b |
52.1 |
4914 |
87.8 |
30,000 |
23196a |
708 |
1.00 |
20.2a |
54.1 |
2924 |
52.2 |
Level of significance |
***‡ |
NS§ |
NS |
** |
NS |
NS |
NS |
Trial mean |
20274 |
771 |
1.13 |
22.0 |
53.2 |
4569 |
81.6 |
†Within a column, treatments with the same letter performed statistically similar.
‡Treatments were significantly different at the following p values ** 0.05 < p > 0.01; ***p < 0.0001.
§NS- not statistically significant.
DISCUSSION
These two specialty grain corn varieties were selected for this trial due to their differences in growth characteristics and kernel starch types. Cascade Ruby-Gold is a short stature, flint corn while Wapsie Valley is a very tall dent corn. The flint corn had a greater potential to produce tillers and the dent corn had lower potential to producer tillers. We hypothesized that these characteristics may impact their response to plant population. Cascade Ruby-Gold had more barren plants and a higher percentage of plants lodged compared to the Wapsie Valley. However, despite this, both varieties yielded similarly (over 2 tons ac-1) and neither were impacted by plant population. Standard recommendations form modern dent corn varieties range from 26,000 to 28,000 plants per acre. In this study, seeding rates from 20,000 to 30,000 seeds ac-1 were planted however the final plant populations only ranged from 17,152 to 23,196 plants ac-1. These data suggest that both flint- and dent-type corns may still produce significant yields at seeding rates lower than the recommended rates for modern grain. However, it is unclear if higher yields of flint and heirloom dent corn could be achieved at standard grain plant populations. Identifying optimum plant populations for flint and heirloom dent corn is critical to help farmers maximize yields of these high value corn types. As these data only represent two varieties planted at one location over one season, additional information should be consulted before making management decisions.
What consumer food products are each flint corn variety suitable for producing? Work is ongoing in 2022 to determine best use for the varieties of corn in the trial.
Which flint corn varieties result in food products that best meet consumer aroma and flavor preferences? Work is ongoing in 2022 to determine consumer preference for varieties of corn in the trial.
No results or conclusions have been generated to date as we are still in data collection phases.
Education & Outreach Activities and Participation Summary
Participation Summary:
In 2021, outreach was limited due to COVID-19 pandemic. During the winter months only online education was possible. In the fall of 2021, a small gathering was held to highlight the flint corn research as well as a sensory program.
Sensory Orientation with the UVM Descriptive Sensory Analysis Panel
During the first and second quarters of 2021 we conducted six sensory orientation sessions with approximately eight of our trained tasters at UVM. These sessions are the first step in developing a Profile Attribute Analysis (PAA) ballot that will be used to assess tortillas and tortilla chips produced with flint corn samples that are part of the study.
The two participating companies, All Souls Tortilleria and Vermont Tortilla, provided samples for use in the orientation sessions. Four of the sessions focused on corn tortilla chips and two focused on corn tortillas. The UVM tasters screened the samples using Modified Flavor Profile to identify critical aroma, flavor, and texture characteristics. The next step will be to incorporate these sensory characteristics in a PAA ballot, and the UVM descriptive sensory analysis panel will optimize it by objectively assessing a range of corn products in the market. Once the ballot is finalized it will be used by the UVM panel to evaluate tortillas and tortilla chips produced by the participating companies using the study flint corn samples.
Flint corn production was highlighted at the NWCS fall field day held in collaboration with Roger Rainville at Borderview Research Farm (program advertisement). There were 125 attendees at the field day. Attendees were able to hear about the corn research and observe the flint corn varieties. We also conducted a sensory workshop at the UVM annual field day, with a focus on corn. The two participating companies provided samples of tortilla chips and tortillas, and UVM provided samples of ground corn. About 50 participants were split into two groups and each group attended one of the two 1.5 hour sessions. During the session, UVM’s sensory expert, Roy Desrochers, facilitated an interactive tasting that covered the basics of sensory analysis and then methods used to assess corn samples and corn products.
A research report was generated to summarize the results of the corn variety by seeding rate trials. The report was posted to our website (https://www.uvm.edu/sites/default/files/Northwest-Crops-and-Soils-Program/2021%20Research%20Rpts/2021_Grain_Corn_Variety_x_Seeding_Rate_Trial_Report.pdfuvm.edu/extension/nwcrops).
Researchers and farmer collaborators developed the Culture of Corn Webinar Series that was held in the winter of 2021. This was a 4-part series that was interactive and covered several aspects of corn history, culture, agronomics, processing, and end-use. Due to the interactive nature of the webinars each webinar was capped at 50 participants. The flyer and series details can be found in the program advertisement.
As part of the Culture of Corn series, we conducted a virtual sensory awareness workshop with a focus on corn. Fifty participants were shipped a box containing various aroma and flavor reference products, as well as a set of various ground corn samples. The 2-hour session included a review of the basics of sensory analysis including basic tastes sweet, sour, salty, and bitter, aromatics detected in the nose, mouthfeels, and textures. After practicing with basic sensory analysis, participants were guided through a sensory session evaluating a range of ground corn samples for aroma, and flavor of water extracts made with the samples. Lastly participants we educated to interpret the meaning of the assessment values relative to consumer acceptance and preference.
A short YouTube video, approximately 5-10 minutes in length, was made with All Souls Tortilleria describing the process of nixtamalization for tortillas and tortilla chips and the corn qualities that lead to high quality tortilla products. The video was one part of the Culture of Corn Series and is posted to our YouTube channel https://www.youtube.com/user/cropsoilsvteam(2, 390 subscribers). The video Behind the Scenes at All Souls Tortilleria and Moon & Stars Arepa Cart can be accessed https://www.youtube.com/watch?v=XLf4TDmMn1U.
Learning Outcomes
None to date as we are still in the planning and planting stage
Project Outcomes
None to date as we are still in the planning and planting stage
No assessment possible at this point.
Information Products
- Impact of Seeding Rate and Variety on Yields of Flint Corn (Fact Sheet)
- Heirloom Grain Corn Variety x Seeding Rate Research Report (Fact Sheet)
- Flint Corn Sensory Research Results (Fact Sheet)
- Sensory Training Presentation (Conference/Presentation Material)
- Flint Corn Variety Evaluations (Bulletin)