Jun. 01, 2022
While growers are often paid based on the physical characteristics of the fruit (e.g., color, size, lack of defects, texture), it is important to consider the flavor of the fruit, as this is the primary driver of repeat purchases by consumers.
The fruit flavor is closely related to consumer preference and continued consumption of any given fruit variety and should be strongly considered. Meeting consumer expectations for specific fruit flavors not only drives consumers to buy more fruit, but also allows growers to increase profitability. Consumers are willing to pay higher prices for distinctively flavored varieties that will enhance their experience of eating fresh fruit.
Flavor is described as the interaction between taste and aroma. Flavor is related to the proportion and intensity of non-volatile compounds, particularly sugars and acids. Five types of receptors in the tongue detect sugars and acids - sweet, sour, salty, bitter and fresh (protein flavors, represented by glutamate). Volatile compounds that produce fruit aromas are detected by more than 650 olfactory nerve endings found in the nose.
The sweetness of fruits is influenced by the amount and composition of sugars. Higher sugar content in fruits increases the sweetness of fruits. In addition, different forms of sugar can affect the sweetness of fruits. In fruits such as apples, peaches and plums, the main sugars present are sorbitol, sucrose, fructose and glucose. Each of these sugars has a different degree of sweetness. Fructose is 1.7 times sweeter than sucrose, while glucose and sorbitol are only 0.8 and 0.6 times sweeter, respectively. For example, if one apple variety has a higher fructose content and another variety has a higher glucose content, the former will taste sweeter.
The acidity of fruits is influenced by the content and composition of organic acids and the amount of each acid in each fruit. For example, the major acid in apples, peaches and plums is malic acid.
The balance between sweetness and acidity of the fruit based on the amount and composition of sugars and acids is important in developing complex and interesting flavors to enhance fruit flavor.
Another key component of flavor is aroma. Fruit aroma is influenced by the amount and composition of volatile compounds. Volatiles known to influence fruit flavor include esters (fruity), alcohols (fruity or earthy), aldehydes (slightly grassy and bitter), lactones (peach-like aroma) and terpenoids (fragrant oil aroma) . Studies have shown that the flavor intensity of fruits is related to the amount and composition of volatiles present. For example, strawberries with higher levels of certain key volatiles are perceived by consumers as sweeter and more desirable than other strawberry varieties that lack these volatiles.
Fruit flavor can be measured instrumentally as well as through sensory science. Sensory science is a multidisciplinary field that uses scientific measurements to explain human responses to sight, smell, taste, touch, and hearing. This form of science is able to relate products to people in a direct way.
Instrumentally, the sugar content of fruit is determined by measuring the soluble solids content using a portable refractometer. Refractometers measure the degree of bending of light as it passes through the sample, which correlates with a specific percentage of sugar in the fruit, and therefore with fruit sweetness. Titrimetry measures the number of major acids in the fruit, which can also be measured and calculated using a portable acidity/pH meter.
Measuring aroma volatiles using portable instruments is challenging. They are quantified by using gas chromatography-mass spectrometry (GC-MS), a laboratory-based technique that helps to separate and identify gaseous compounds based on their mass.