Cracking the Code of Texture:

Blueberries are a beloved fruit, enjoyed for their pleasant flavor and health benefits. The production of blueberries has increased almost 5-fold during the last 20 years largely due to successful breeding efforts that have expanded the areas suitable for their production. My research is focused on helping breeding programs develop blueberry varieties with a firmer texture that is appealing to consumers while protecting the berries from damage during harvest and transport.

Fruit texture is one of the fruit quality traits that can change drastically during transport and storage and can have significant consequences on both consumer experience and marketability. Currently cultivated varieties (cultivars) often produce fruit with variable texture that fails to consistently meet consumer expectations. Moreover, fruit from most cultivars are insufficiently firm and susceptible to internal bruising, making it challenging for machine harvest. As a result, developing blueberries with firmer berries that do not soften quickly during storage has become a crucial goal for breeding programs.

To develop cultivars with improved texture, we need to first understand the nature of blueberry texture and identify means to appropriately measure it. Texture is a complex trait, determined by many factors such as cell wall composition,

turgor, and biochemical constitution. Measuring or quantifying texture is a complicated task as well. My research with others at the Plants for Human Health Institute at NC State University is aimed at finding the best way to assess the texture of blueberry fruit. Simple instruments that measure a single mechanical parameter have been widely used in the blueberry industry. However, our findings suggest that one parameter is not enough to understand the complex characteristics of fruit texture. Our research group, in collaboration with international scientists, developed a method that can dissect the blueberry texture using 17 mechanical parameters. The abundance of parameters allowed us to examine the texture of blueberries with much higher resolution.

Further investigation into the rich data obtained from 17 parameters suggested that the mechanical texture of blueberries is mainly determined by four components. Each component contributes in its own way, and different parameters should be used to measure different components. For example, the stiffness or resistance to deformation can be measured using parameters called ‘F1mm’ (force measured at 1 mm depth) or ‘Young’s Modulus’ (function of force vs. strain). Another example is the sensory perception of hardness, springiness, or crispness having high correlation with a parameter called ‘FM’ (maximum force measured at skin break). The take-home message here is that blueberry texture cannot be understood by just one component; it is important to collect data for different components to evaluate different aspects of texture. To accomplish this, multiple parameters need to be assessed and not one.

One challenge that has long faced the blueberry industry is its limited shelf-life. Blueberries are susceptible to rapid softening during storage, which limits shelf-life to two to four weeks. Recent research conducted by our team has aimed to tackle this issue by understanding how the texture components change during storage and developing new methods to predict this change. We were able to develop prediction models that could be used at the time of harvest to identify genotypes that would undergo substantial texture change and those that would stay firm during storage. This discovery is key to more quickly and efficiently screening blueberry germplasm—a pool of plant material that carries the genetic information for breeding—so that new blueberry varieties with longer shelf-life performance can be developed and provided to farmers.

Participating in the FFAR Fellows Program has significantly advanced my personal and professional growth. Through this experience, I have improved my research capabilities, strengthened my teamwork skills, and cultivated leadership qualities. I am immensely grateful to FFAR and my sponsor, NCSU Plants for Human Health Institute, for providing me with this great opportunity. I also want to express my deep appreciation to my advisors, Dr. Massimo Iorizzo and Dr. Penelope Perkins-Veazie, for their encouragement and support throughout this journey.