Specialty Pumpkin: Laying the Groundwork for an Emerging Crop and Lucrative Products

Objective 1: Assess potential risks/benefits of specialty pumpkin production and barriers to acceptance.

Team: Jorge Ruiz-Menjivar and Marilyn Swisher

Activity 1: Consumer survey to understand consumer perceptions, preferences and willingness to pay for specialty pumpkin based on country of origin, certification labels other food product attributes.

Institutional RevIew Board approval. We obtained IRB approval to collect data with 450 American consumers via Qualtrics (IRB202000525)

Survey Development.

• Informed by the extant literature on food preference for new food products, native foods, and consumer demand for fresh produce. ​
• Conceptual model guided by the Theory of Planned Behavior-TPB (Attitude, Subjective norm, Perceived behavioral control, and Behavioral intention)​
• Design of Discrete Choice Experiments (DCE) with five attributes.
  • • Nationally representative panel accessed via Qualtrics XM (Predetermined quotas: Gender (F: 52%; M:48%), Age (18-34: 30%; 35-54: 32%; 55+: 38%), Race (White: 75%; Non-White: 25%), and Ethnicity (Hispanic/Latino: at least 30%). ​Inclusion criteria: U.S. Adults 18+ and must have consumed/ purchased fresh pumpkins or butternutsquash for cooking purposes within the last two months.​

    • Example of choice set presented to respondents

       

      • Structure: (a) Informed consent and inclusion criteria Q's; (b) cooking Q's, food neophobiascale, consumer trust scales, TPB Q's; (c) Importance of Calabaza attributes and (d) Discrete Choice (DC) experiment. 

      We used scales such as the Food Neophobia Scale (Rabadán, & Bernabéu, 2021), validated instruments measuring Food Agency, Skills and Confidence (Wolfson et al., 2020), and Trust (farmer, retailer, and government and supply food system).

      Rabadán, A., & Bernabéu, R. (2021). A systematic review of studies using the Food Neophobia Scale: Conclusions from thirty years of studies. Food Quality and Preference, 93, 104241.

      Wolfson, J. A., Lahne, J., Raj, M., Insolera, N., Lavelle, F., & Dean, M. (2020). Food agency in the United States: associations with cooking behavior and dietary intake. Nutrients, 12(3), 877.

      Data collection. We collected data from 450 American consumers in February 2022.

      Sample: 450 American consumers​

    • Compensation: $9.26 per respondent.​

  • Analysis.  Descriptive statistics and Partial Least Squares Structural Equation Modeling (PLS-SEM).

• Cross-check questions (Birth year and Age) and Survey completions under 5 minutes were not deemed valid.

• Activity 2: Interviews with actors in the distribution system and sales points ranging from farmers’ markets to traditional commercial outlets, to identify key bottlenecks and opportunities to market in a variety of venues. ​

   

  Main goals​

  • Understand the barriers to carrying calabaza in different venues ​
  • Identify opportunities to address those barriers through breeding​

  Target Populations​

  • General managers, produce managers and others who participate in decisionsabout the produce stocked in a given venue​
  • Covers a range of venues beyond the standard chain supermarket​
  • Includes a focus on points of sale in venues serving Latinx, Afro-Americanand Afro-Caribbean and other clientele groups who have a food culture heritage of consuming calabaza​
  • Conducted in Spanish when appropriate

   

  Activity 2.1: Accommodation to Consumer Preferences – This information is currently being collected from results forthcoming after completion of point-of-sale interviews.

  Activity 2.1: Identify traits of calabaza that both consumers and grocers want that can be generated through breeding​

  • Procedures: Present key findings regarding traits that are critical forconsumers (based on our survey) to the point-of-sale decision-makers​
  • Ascertain degree to which the point-of-sale can or will accommodatethe consumer preferences identified​
  • Example: Consumer preference for chopped calabaza adds cost at the point-of-sale for labor, chilling, and possibly traying – will this be a major barrier tocarrying calabaza?

   

  Activity 2.2: Identify other traits of potential importance to grocers as barriers or as incentives – This activity is currently in progress with results forthcoming after completion of point-of-sale interviews.

  • Seasonal availability​
  • Size of the squash​
  • Color of the squash rind and flesh​
  • In-store perishability​
  • Size of standard shipping units (e.g., bin vs. 50lb box)​
  • Value of the Fresh from Florida identity for calabaza​
  • Value of country-of-origin labelling​
  • Information about how to prepare the squash, including recipes

   

  Activity 2.3: Differences among clientele groups – This activity is currently in progress with results forthcoming after completion of point-of-sale interviews to include different cultural groups.

   

  • Understand the incentives for and barriers to carrying calabaza in the sales points that are frequented by different cultural groups ​
  • Both consumer and vendor preferences may vary based on different foodways

   

  Next Steps for Activity 2:

  • Conduct cognitive test of proposed interview protocol with at least three point-of-sale representatives and make revisions as needed​ IRB approved grocer interview #IRB202000525. First cognitive test resulted in a need to revise the instrument.  It showed that grocers could not answer some of the questions and revealed that further clarifying information needed to be included.  Additional input was obtained from two UF colleagues, Gene McAvoy and Dr. Rose Koenig, both with extensive experience in marketing fresh produce.  McAvoy is the Associate Director for Stakeholder Relations at the Southwest Florida Research and Education Center.  He has over fifty years’ experience with temperate and tropical environments including fourteen years’ experience living and working in Africa and the Caribbean.  Dr. Koenig is the interim director for the Global office for the University of Florida Institute of Food and Agricultural Sciences and a lecturer at the University of Florida. She previously worked with the Rodale Institute in Africa, operates a 17-acre organic farm with one of the state’s first Community Supported Agriculture programs, and has helped establish two farmers’ markets.

  Second cognitive test resulted in an answerable instrument.

  • Secure IRB approval for human subject research, including both Spanish-languageand English-language versions of the research instruments and statement of informed consent​.  Revised IRB has been translated to Spanish and Chinese.  These versions are awaiting IRB approval.
  • Complete 10 interviews and conduct qualitative analysis of the data​. Data collection is still in progress. Thus far, three interviews have been conducted from contact with 41 points of sales in venues serving Latinx, Afro-American, Afro-Caribbean, Asian, and other clientele groups. During the interviews, the instrument was successful. The difficulty is the availability of produce managers at the various venues.  These managers report being extremely busy especially due to a labor shortage.  They seem willing, but they just do not have the time.
  • Prepare grower interview protocol​. Grower interview protocol is being prepared with expectations of commencement in early summer.

   

  Activity 3: Interviews with farmers to identify key barriers, opportunities and research priorities for specialty pumpkin production. 

   

  Main Goals:

  • Assess grower interest in producing calabaza among non-producers​
  • Assess existing grower interest in increase calabaza production ​
  • Both consumer and vendor preferences may vary based on different foodways,necessitating different accommodations to their needs​

  Next Steps​

  • Conduct tests of current interview protocol andmake adjustments as needed​
  • Include key findings of consumer and grocer studies to clarify their needs togrowers​
  • Target populations: current and potential producers with an emphasis onLatinx, Afro-Caribbean and Afro-American growers

Objective 2: Evaluate pumpkin germplasm lines and cultivars for use as flesh, seeds, and as product ingredients.

Team: Andrew MacIntosh and Amy Simonne

Activity 1: Pilot study to examine utility of calabaza for ale fermentation

Materials and methods:

After receiving 4 bulk plastic containers of tropic pumpkins from The University of Florida Horticulture, a full analysis was conducted. The majority of the pumpkins were cut, roasted, and delivered to First Magnitude, a local brewery that is a commercial partner to create a pumpkin beer. The final product First Magnitude created turned out quite well as the product sold at a much faster rate than anticipated.

Researching the fermentability of each pumpkin line was conducted in the Food Processing and Engineering lab at the University of Florida. This process began by taking a representative sample from each line of pumpkin. The flesh from 3 different pumpkins per line (except for P57) was added to a blender to be homogenized.  Creating this puree consisted of adding 0.6 kg of pumpkin with 0.5kg of water to create enough pumpkin juice to run a fermentability experiment.

After individually blending each line with those approximate weights, the scientists allowed the pumpkin puree to sit in the fridge for 24 hours to allow all of the fermentable sugars to dissolve into the liquid. Each puree was separately centrifuged to separate the solids from the liquid. After spinning the pumpkin puree at 7000rpm for 10 minutes, the juice was decanted.

The pumpkin juice was then analyzed using a density meter analysis 35 (DMA 35) from Anton Paar to preliminary access the sugar level. Using the line of pumpkin juice with the lowest Plato, each other sample was diluted to the baseline sugar level. Having the same sugar level for each line of pumpkins is crucial to be able to compare how fermentable each line of pumpkins is. Using an American Society of Brewing Chemists (ASBC) standard method for accessing fermentable sugars, 250mL of pumpkin juice was added to duplicate flasks. The Standard method called for 1g of yeast per flask and post fermentation data has collect and analyzed. 

Samples of the pumpkin juice pre and post fermentation were assessed with using an Alcohol Extract Meter 500 (ALEX 500) from Anton Paar and a spectrophotometer from Shimadzu. The ALEX 500 is used to give data about the density, alcohol, and sugar content of the juices to correlate changes before and after fermentation. The spectrophotometer is used to correlate the color of the juice to a visible light wavelength and how intensely the light is absorbance by the sample. 

Another method to assess the pumpkin lines was a texture analysis test. Using Stable Micro Systems TA.XTplusC Texture Analyser to assess parameters of the flesh and the hardness of the skin. Using a standard program for each sample with a standard size of 3cm cubes to accurately determine the differences.

Activity 2: Pilot study to examine rind thickness and flesh hardness

Materials and methods:

Texture analysis test was conducted to assess the pumpkin lines rind thickness. A Stable Micro Systems TA.XTplusC Texture Analyser was used to assess parameters of the flesh and the hardness of the skin. Using a standard program for each sample with a standard size of 3cm cubes to accurately determine the differences.

Objective 3: Determine yield, fruit quality and disease resistance of tropical pumpkin cultivars in the Southeastern U.S. and Puerto Rico in organic and conventional cropping systems and determine phenotypic relationships among nutrition, flavor and fruit size traits in select germplasm.

Team: Geoffrey Meru, Angela Ramírez, Andre da Silva, and Carlene Chase

Activity 1: Conventional trial in Florida

Materials and methods

Initial conventional field trials were conducted for ten cultivars in Homestead FL and Live Oak FL. Seedlings were transplanted at 3 weeks in plastic mulch. Plant management (nutrient and pest management) followed UF/IFAS guidelines for pumpkin production in Florida.  The germplasm will be evaluated using a randomized complete block design consisting of three plots, each plot with 5 plants. In-row spacing will be 3 ft, while 6ft between-row spacing will be applied. Data was collected on growth habit (bush or vining), flowering time (days to male or female flowering), fruit size, fruit shape, plant vigor, vine length, disease/ insect tolerance, and yield (fruit and seed). At harvest, representative fruits per plot per cultivar will be processed to determine fruit quality attributes including, flesh color, flesh thickness, seed-cavity size, and degree brix. Data was analyzed using the GLM procedure of SAS (SAS Institute Inc., Cary, NC).

Activity 2: Organic and conventional trial in Puerto Rico

Materials and methods

Seed distribution was performed early in 2022 for evaluation of UPRM materials in Florida. To accomplish objective 1, one undergraduate student was hired for field and pumpkin processing work. Two trials were performed under the UPRM AES facilities at the Organic Research Farm and Conventional site at the UPRM Lajas Substation.  The Lajas substation is located at 18◦030 0000 N, 67◦0303400 W at 9 m above the sea level. Lajas has soils belonging to the Mollisol and Vertisol orders, and has temperatures between 19 to 33 ◦C, an annual precipitation of 1143 mm, and an average relative humidity of 80%. Genotypes were seeded in a greenhouse in Lajas on 6 December 2021 in a commercial planting mix (ProMix®; Premier Tech Horticulture, Quakertown, Pennsylvania). Seedlings were watered daily. Seedlings were kept in a greenhouse (14 days) until being transplanted to the field. that were moved outside for hardening. Fourteen -old seedlings were transplanted to the field and arranged in a randomized complete block design with three replications at each production system. Seedlings were planted on raised beds [1.83 m center-to-center] with drip irrigation (perforations 12 inches apart) no plastic mulch was used. The experimental unit was 4.6 m with a planting distance of 0.91m for a total of 5 plants per experimental unit.

Objective 4: Develop cropping systems for sustainable organic and conventional specialty pumpkin production.

Activity 1: Organic system trial and nutrient cycling study in North Florida

Team: Carlene Chase and Gabriel Maltais-Landry

Materials and methods 

In 2021, ten pumpkin lines were evaluated in a reduced tillage system with roller-crimped rye used as mulch on certified organic land at two field sites, the Plant Science Research and Extension Unit, Citra, FL (29.4103°N, 82.1448°W) and North Florida Research and Education Center – Suwannee Valley (30.3020°N, 82.8978°W). The pumpkin germplasm lines were UFTP8, UFTP22, UFTP24, UFTP38, UFTP42, UFTP45, UFTP46 (‘La Estrella’), UFTP47, UFTP57, UFTP58 (‘Kakai’). Two additional tilled treatments included ‘La Estrella’ evaluated with the rye incorporated and either left without mulch or with raised beds covered with black plastic mulch.

The reduced tillage system was initiated with the planting of a cowpea (US-1136) cover crop in summer 2020 and ‘Wrens Abruzzi’ rye was planted after roller-crimping cowpeas in late fall 2020. The rye was roller-crimped in spring 2021. Two-week-old pumpkin seedlings were transplanted two weeks after rye termination (04/22/2021 at Citra; 04/29/2021 at Live Oak). Dates of first male and female flowers were recorded. Pumpkin fruits were harvested approximately 100 days after transplanting. The data collected included fruit number and weight, fruit flesh thickness, diameter, and flesh color.

Soils were sampled in both Citra and Live Oak 1) at rye cover crop termination, 2) after fertilization and pumpkin transplant, and 3) at pumpkin harvest. For these soils, inorganic N were quantified at sampling and N release using incubations, in addition to carbon soil health indicators (permanganate oxidizable carbon [POXC], loss on ignition [LOI]). Soil sampling focused on the three systems used for cultivar UFTP46: mulched rye, rye incorporated without plastic mulch and rye incorporated under plastic mulch. Nutrient concentrations were also quantified in harvested pumpkins for cultivar UFTP46 under the three rye management systems, in addition to three germplasm lines (UFTP38, UFTP42, UFTP57) that showed promising yield in organic conditions.

The trials are being repeated for the 2022 season for which cowpea and rye were planted in summer and late fall 2021, respectively. Cowpea cover crop biomass was sampled at cowpea termination and prepared for nutrient analyses. Soils were sampled at cowpea termination to quantify soil N and conducted incubations to quantify N release from cover crop mineralization. Soils have been pre-processed for soil health indicator quantification. The rye will be terminated in spring 2022 followed by pumpkin transplanting. Rye biomass will be sampled for nutrient concentrations. Following rye termination, we will repeat plant/soil sampling and measurements conducted during the 2021 pumpkin growing season.