# What's in Your Fruit Juice?--Rapid Quality Screening Based on Infrared (FT-IR) Spectroscopy
###### Abstract
Strawberry and cherry juices experienced 58% and 35% loss, respectively, after 28 days of refrigerated storage [13]. [PERSON] and others observed that the initial yellow passion fruit juice formulation had negligible ascorbic acid content (\(<\)5 mg/L). However, when the juice was fortified with 450 mg/L of ascorbic acid and subjected to pasteurization (85 \({}^{\circ}\)C for 30 min), a 25% ascorbic acid reduction occurred, leading to the complete loss of ascorbic acid after 14 days of storage at 37 \({}^{\circ}\)C [14]. On the other hand, citric acid, a naturally occurring weak organic acid that is concentrated in citrus fruits, serves as a common food additive to enhance acidity, improve the sour taste in foods and beverages, and ensure product stability [15]. Studies have shown a correlation between the excessive consumption of sugar-sweetened beverages (SSBs), including FJs, and weight gain in both adults and youth [16; 17; 18; 19; 20]. This excessive intake has also been associated with various health issues, such as obesity, diabetes, cardiovascular diseases, and fatty liver syndrome [21; 22; 23; 24; 25; 26]. Even though the primary health risks are attributed to high fructose corn syrup (HFCS), beverages that substitute HFCS with cane sugar or the crystalline form of fructose, which may look like a healthier alternative and have a positive consumer perception, still raise concerns due to their high total sugar and fructose content [26]. Besides the risk of obesity, diabetes, cardiovascular diseases, and triglyceride deposition in the liver, fructose is linked to insulin resistance and kidney stones [26]. Despite the nutrition label on FJs requiring the disclosure of total sugar content in grams, complete information about the individual sugar content is not mandated. This lack of specificity allows for the potential substitution of fructose for glucose, given that an equivalent amount of fructose is sweeter than glucose [26]. Studies have also revealed that 100% fruit juices contain no fewer calories than SSBs, while they contain a limited amount of nutrients and carry a similar risk of obesity as SSBs [27; 28; 29]. The nutritional labels for pre-packed foods, mandatory and regulated by government agencies worldwide, are overseen by the Food and Drug Administration (FDA) in the US for food products other than meat and meat products, and in the European Union, the European Commission regulates the nutritional labels [30; 31]. The FDA ensures compliance with labeling regulations by randomly analyzing collected food products and applying different criteria for different nutrients [32]. For instance, if vitamin C is added to an FJ for fortification, it must be present in the product at 100% or more of the declared value on the label. In other words, the laboratory analysis must confirm that the nutrient content is equal to or exceeds the value stated on the label when vitamin C is added to fortify an FJ. However, if vitamin C is a naturally occurring nutrient in the FJ, then it must be present at 80% or more of the declared value [32]. On the other hand, the total sugar content in an FJ product cannot exceed the declared value on the label by more than 20% [32]. The FDA generally tolerates reasonable excesses of vitamin C and reasonable deficiencies of total sugars within good manufacturing practices [32]. Our objective was to simultaneously predict multiple quality traits (soluble solids, sucrose, glucose, fructose, total sugars, titratable acidity, citric, and ascorbic acids) of FJs using a field-deployable portable FT-IR sensor that requires no sample preparation.