The electronic nose (e-nose) is designed to crudely mimic the mammalian nose in that most contain sensors that non-selectively interact with odor molecules to produce some sort of signal that is then sent to a computer that uses multivariate statistics to determine patterns in the data. This pattern recognition is used to determine that one sample is similar or different from another based on headspace volatiles. There are different types of e-nose sensors including organic polymers, metal oxides, quartz crystal microbalance and even gas-chromatography (GC) or combined with mass spectroscopy (MS) can be used in a non-selective manner using chemical mass or patterns from a short GC column as an e-nose or “Z” nose. The electronic tongue reacts similarly to non-volatile compounds in a liquid. This review will concentrate on applications of e-nose and e-tongue technology for edible products and pharmaceutical uses.

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Limonin and nomilin are two bitter compounds present in citrus and are thought to cause off‐flavor in Huanglongbing (HLB)‐infected fruit/juice. This study determined the best estimate thresholds of limonin, nomilin and their combination in matrices composed of sugars and acids at levels found in orange juice, and in orange juice, using the three‐alternate forced‐choice methodology. Further, the effect of sucrose or citric acid in orange juice on the bitterness perception of both compounds was investigated. In a simple matrix (sucrose and citric acid), the threshold of limonin was 4.0 mg/L, lower than the threshold of nomilin, which was 5.4 mg/L. Together in a 1:1 ratio, limonin and nomilin acted synergistically and both thresholds decreased. When adding nomilin at a fixed subthreshold concentration of 2 mg/L, limonin threshold decreased to 2.6 mg/L. Recognition thresholds in orange juice were 4.7 and 2.6 mg/L for limonin and nomilin, respectively. Added sucrose, but not citric acid, decreased the perception of bitterness induced by limonin and nomilin in orange juice. Practical Applications Florida orange juice processors are encountering increased juice bitterness resulting from elevated levels of the bitter compounds limonin and nomilin due to citrus greening or Huanglongbing disease (HLB). Increased knowledge of sensory perception of limonin and nomilin in orange juice will help processors determine the final quality of juice made with fruit from groves infected with HLB. In a model solution, nomilin decreased the perception threshold of limonin. In orange juice, recognition thresholds were 4.7 and 2.6 mg/L for limonin and nomilin, respectively, suggesting that orange juice containing such levels of these two compounds would taste bitter. As sucrose decreased bitterness perception of juice spiked with limonin and nomilin, blending with juice having higher sugar levels could be used for bitter off‐flavor management for juice made with fruit strongly affected by the disease.

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“Tommy Atkins” and “Palmer” mangoes were harvested medium‐ripe held for 7–20 days at five different temperatures and evaluated for quality attributes. The objective of this work was to obtain quality curves at chilling and nonchilling temperatures and to identify, for each temperature, which quality factors limit mango marketability. Chilling injury and increased fruit softness were the limiting quality factors for mango stored at 2 and 5C. Softening of the fruit, changes in color and development of decay were the limiting quality factors for mango stored at 12, 15 and 20C. Prediction of mango shelf life calculated from the data reported in the literature is not precise unless the characteristics of the fruit and environmental factors involved are well known. The curves obtained from quality evaluations for each temperature showed that a single quality attribute cannot be used to express loss of quality of mango over the normal physiological range of temperatures.