ABSTRACT
Fruit juice is known as a healthy food product, and is currently consumed by a large percentage of the global consumer population (Verbeke 2005). Fruits are healthy foods because they are rich in antioxidants, vitamins, dietary fiber, and minerals. In addition, fruits do not contain any dairy allergens such as casein and lactose (Luckow and Delahunty 2004). It has also been suggested that fruit juice serves as a good medium for probiotics (Tuorila and Cardello 2002). All these characteristics of fruit juice are very important in the purchasing decisions of consumers. However, another significant factor affecting consumer satisfaction, and consequently influencing the purchasing decision, is the quality of the product. Quality is a key product component, and it can be determined using objective or subjective measurements. Objective evaluation involves the use of laboratory instruments with no involvement of the senses. Subjective evaluation is done by either trained or untrained human
7.1 Introduction .................................................................................................. 137 7.2 Sensory Attributes of Fruit Juice .................................................................. 138 7.3 How to Measure Fruit Juice Quality Using Sensory Evaluation? ................ 139 7.4 Advantages and Disadvantages of Sensory Analysis to Measure
Fruit Juice Quality ........................................................................................ 141 7.5 Applications .................................................................................................. 142
7.5.1 New Product Development ............................................................... 143 7.5.2 Marketing and Consumer Characteristics ........................................ 143 7.5.3 Comparison of Sensory and Instrumental Measurements................ 144 7.5.4 Assessing Product Quality ................................................................ 145
7.5.4.1 Effect of Processing Conditions: Temperature .................. 145 7.5.4.2 Effect of Product Properties: Composition,
Ingredients, and Concentration .......................................... 146 7.5.4.3 Effect of Unit Operations and Processing ......................... 146
7.6 Conclusions ................................................................................................... 147 References .............................................................................................................. 147
observers (OSU 1998). Food industries often utilize sensory evaluation techniques to test products. The quality of juice is often assessed in terms of three main sensory properties: appearance, flavor, and texture. The visual perception of color is the main appearance attribute in fruit juices and results from the activation of the retina by electromagnetic waves in the visible spectrum. Flavor characteristics include taste and odor. Taste sensations are produced as substances dissolved in the saliva interact with the taste buds in the papillae on the tongue (Weaver and Daniel 2003) and odor sensations are created by those substances that are volatile enough to enter the air in the sensory region and are partially soluble in the mucus that covers receptors (Masson and Nottingham 2002). The texture attributes of juices comprise all these traits, influencing mouthfeel, and the most important texture attribute is viscosity. These three attribute categories are expressed as a continuum and not as discrete properties.
