Blueberries, onions and other crops

So many crops, so little time. Blueberries, onions, snap beans, peppers, rockmelons, broccoli, bananas and apples. Then there was bread and wine and rice and baby food. Why couldn’t I ever focus on only a few foods?

sign on a farm gate: Pepperland Cherokee Receiving Station
Farm in Tennessee where we harvested pimiento peppers. Photo by Virgil Esensse.

My thirty years of research at the University of Georgia were great. Almost half of those years were in Griffin. Athens occupied the rest of my career. Those who knew me knew that I enjoyed teaching more than research. I devoted much of my time to undergrads. My grad students missed out on time and attention they deserved.

Dr. William Bramlage taught one of my favorite college courses, Postharvest Physiology. Postharvest physiology studies the biological changes in plant organs after harvest. Most postharvest research focuses on fruits and vegetables. It also extends to flowers and other plant parts. Fresh fruits, vegetables, and flowers are alive, continuing to respire, senesce and die. Traditional food processes halt those biological changes. Postharvest technology focuses on techniques to maintain quality of fresh items.

My PhD research investigated fish muscle physiology postmortem. I moved south to the Georgia Experiment Station to study fruits and vegetables. The mobile lab took us to fields of peas and greens. We followed the peas from the field to a canning plant and the greens to a freezing plant. Stan and I engaged an economist, Jeff Jordan, to help round out our Postharvest Systems Team. Jeff told us that we were wasting our time looking at processed fruits and vegetables. The action was in fresh. My entire career hinged on that insight.   

postharvest systems research team posing in front of the mobile lab
Left to right: Stan Prussia, Bill Hurst, Rob Shewfelt, Jeff Jordan

Blueberries. My first real research project was my MS work at the University of Florida. I looked at five possible sources of anthocyanins as natural colorants. Blueberries and red cabbage turned out to be the two most promising possibilities. Blueberries produced a more stable, bright color than red cabbage. When extracted the blueberry pigments came out dark red. Turns out that the blue in the fruit results from an aluminum-anthocyanin complex. Extraction breaks up that complex. I used colorless Kool-Aid to test the potency of the extracts. Sensory tests were only visual. The extraction process was nasty and turned me off to natural colors.

I completed an in-depth literature survey before venturing out to pick blueberries. My wife came along for the adventure. I learned about highbush and lowbush blueberries and asked the grower to tell me what type they were. I needed this information for my thesis write-up. He told me that they were rabbiteye blueberries. No, I need to know if they are highbush or lowbush! Rabbiteye would not cut it in my thesis. Dismayed, I went searching in the literature. I found a University of Georgia Bulletin by William Brightwell on rabbiteye blueberries. Who knew?       

Fast forward 35 years. I worked on a funded project with a group of scientists from Florida, Georgia, and North Carolina. Plant breeders introduced new varieties of fresh highbush blueberries developed to withstand mechanical harvesting. We compared durability and consumer acceptability of several ‘crisp’ and traditional berries. Another goal was to reduce migrant labor for picking. A large contingent of UGA researchers descended on Waldo, Florida, the location of the test plots. We arrived in the early afternoon to walk around the rows of blueberry bushes and see the harvester at work. Gerard showed us how to pick the berries in a quick manner without damaging the fruit. It is not as easy as it looks.

After spending the night in local accommodations, we were ready to start a long day. Picking started after the dew lifted. We labelled each set of samples and placed them in containers for a trip to Tifton, Georgia, 150 miles away. A sorting table awaited us there. With it we determined yields and assessed damage for each treatment. By the time we finished it was about 4AM, and we were all exhausted. Most of the Food Science group proceeded back to Athens. I opted for a motel in Tifton. The room was inexpensive, very nice, and complete with mirrors everywhere. That part didn’t impress me as I wasn’t interested in observing my grimy appearance.    

Our work was only beginning. We evaluated berry samples for quality, storage stability, and consumer acceptability. As expected, we found that ‘crisp’ berries stood up well to harvesting and handling. The regular ones did not hold up as well. We needed to know if the more durable fruit was as good as the berries we were replacing. We noted that the new selections were sweeter and firmer than the conventional ones. We presented 300 consumers in different locations with blueberries of both types. They were unaware of the differences. Participants preferred the ‘crisp’ varieties over the regular ones. It was clear that breeders had not created an inferior fruit merely to improve distribution. There was one drawback with these new blueberries. When baked in pies, the berries did not pop to release their juices while baking. The pies were tasty but looked weird. Consumers who tasted the pies did not seem to notice the difference. Experienced bakers would notice and would be neither happy nor amused.   

two students in a field transporter at a field day
Unlike most food science students, those in my lab went into the fields. Photo courtesy of Christine Addington.

Onions were not my favorite crop to study. Georgia promotes the sweet Vidalia onion as a state symbol. Georgians claim to be able to eat them like apples. A food scientist in the state needed to test them, and that task fell to me. One secret of sweet onions is that they are not so much sweet as they possess little or no pungency. Several varieties are capable of becoming a Vidalia onion. The other secret? When these varieties grow in low-sulfur soils, they are much less pungent. Sweet onions are found in Texas, the state of Washington, and other locations.

Most of our onion work involved sensory testing. Tasting onions is not rocket science. Put the cut sample in your mouth and chew it with your lips closed. Score it on a 5-point sweetness scale. Open your mouth and any pungency becomes apparent immediately! Consume an unsalted top cracker and a sip of water. Then it is on to the next sample. Three samples were as much as any panelist could handle in a day. Candy-striped, hard, round mints were the reward for panelists. The candies were not sufficient to hide onion breath then or for several hours. Poor Sue Ellen! She prepared all the samples and sought panelists from people in the building. As word spread, potential victims became scarce. Most of those studies were storage tests or variety trials.

taste test for sweet onions. Participants must be 18 years old and will receive 5 dollars. All varieties may not be sweet.
Recruiting poster for onion consumer testing

When I moved to Athens, we recruited a dedicated panel who did all the tasting. Variety trials were part of the study. We tested samples to predict sensory pungency by chemical analysis. We found significant relationships between the chemical test for pungency and sensory scores. Not perfect, but useful. We also related sensory scores to consumer acceptability. Once again, perception of pungency prevailed. Sensory sweetness did not predict acceptability. To help our panel we looked at alternative palate cleansers to crackers and water. None of the ones we tried were as effective as the old standard.      

Peppers took me to Pepperland in Tennessee, Purdue University, Israel, and south Georgia. My first grad student and I traced pimiento peppers from the field to processing plant. Some of these trips were over 100 miles.  Pimiento peppers look similar to red bell peppers but they come to a point rather than the typical bell shape. They are delicious when cored, deseeded, and baked with butter inside. The processing plant peeled; cored; blanched; and the cut soft, red flesh into small pieces. After packing these pieces into small jars, the plant cooked and cooled the product. Our mission was to reduce losses during transport to the plant. The study revealed that canning plants need better coordination between field and processing operations to improve yield.

two research scientists setting up a coring machine with pimiento peppers
Kell Heaton and a pilot-scale model of pimiento coring machine

In a related project Kell Heaton found that decreasing the lye concentration while peeling reduced peel loss. The companies gained major cost savings from his research. In a way he was contributing to sustainability before the concept was cool.

My most basic research involved studying the biochemical mechanism of chilling injury. The initial project involved tomatoes. Bell peppers turned into a more appropriate model. I spent a week at Purdue learning a delicate technique to measure a specific enzyme located in a cell membrane. The project involved collaborators in Tifton, Georgia, and Israel From the work we proposed a mechanism. It’s complicated. Oxidation of cell membranes compromised their efficiency and damaged its proteins.

Towards the end of my career, a grad student worked on bell peppers. Red peppers are green before they turn red. If a pepper stays in the field when changing from green to red, pests and decay decrease yields. It can be harvested when it starts to turn red. These fruits will turn to a full red under more controlled conditions. Red peppers command a higher price. Such de-greening operations present greater economic returns to the grower and less food loss.

rows of melons as grown in Australia
Rockmelon plots where Bob and I hung out

Melons sent me down under to Australia. My research was on rockmelon flavor development. A rockmelon is Australian for cantaloupes and honeydews. My project involved the variety, MacDimon. It looks like a cantaloupe on the outside with flesh like a honeydew on the inside. Its flavor is more complex than either. Our work looked carefully at harvest maturity as measured by days after blossom. I needed to tag each flower in the field. Messages on the bulletin board warned me about Bob, a very poisonous snake seen in the area. I was vigilant for a week or two. Then I relaxed. One morning, I had one hand in the box of tags and one hand on the plant. I felt something move by the plant, and I thought about Bob. I’m not sure who was more scared, the baby frog or me!

Later, I spent hours in front of a gas chromatograph equipped with a sniffing port. Each run of extracted melon volatiles took 30 minutes. I identified the aroma of numerous flavor compounds as they emerged at the port. An early one smelled like dirty socks left in a gym locker too long. A late one was strong with the distinctive aroma of Golden Delicious apples. This mix of many compounds in the ripe melon combine to form a complex, desirable aroma.   

Other crops included broccoli, snap beans, bananas, and rice. We also studied white, whole wheat bread; peach baby food, and red wine. I could go on about what we found with those foods, but I have given you a flavor of my research. I benefitted from wonderful technicians, students and collaborators. Thank you all.  

Next week: Feeding the Other: Whiteness Privilege and Neoliberal Stigma in Food Pantries

Many thanks to Sue Ellen McCullough, Anne Morrison, Joe Garner who handled all the logistics for our many hands-on trips to the fields or for consumer testing. Also to Bob Flewellen, Lary Hitchcock, and Sandra O’Pry for technical support.

To the students:  Kylah Smith, Christine Gianella, Carmisha McKenzie, Katherine Thompson, Ben Addington, Maureen McFerson, Antoinette Menuel, Adrian Kerrihard, Carlos Margaria, Joy Wright, Brenda del Rosario, Guodong Wang, Darlene Cowart, Virgil Esensse, Chia-Pei Laing, Maruj Limpawattana, Danielle Wedral, Srivaskara Balasubramian, Patricia Brennan, Hrvoje Verzi, Meera Deveriya, Jared Henderson, Sara Sparks, Amy Rowley, Katie Robbins, China Reed, and Tung-Yun Lin.  

And my collaborators: Stan Prussia, Jeff Jordan, Bill Hurst, Chi Thai, Rueben Beverly, Elizabeth Baldwin, Stan Kays, Gerard Krewer, Harold Scherm, Dan Macclean, Charlie Li, Doyle Smittle, Norman Schmidt, Hong Zhuang, Reid Torrance, Kell Heaton, Darby Granberry, Al Purvis, Anna Resurreccion, Romeo Toledo, and Joe Frank.

Special thanks to Stan Kays who shared his equipment and expertise with so many of my students and to Liz Baldwin who provided many wonderful research ideas and a second home to students both before and after they graduated.

I apologize to anyone I left out.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s