Honey's valued for nutrition and antioxidants, but adulteration, mainly sugar addition, reduces quality and nutritional value. In this chapter, a detection system for honey adulterated with sucrose syrup is reported using a sensor built with fiber optics. The sensor consists of the union of a segment of non-core multimode fiber (NC-MMF) joined at its ends to two segments of single-mode fiber (SMF). The principle of operation is that, when propagating an optical field in the device, a transmission peak appears at its output due to its filter-like response, the position of which depends on the effective refractive index of the medium surrounding the NC-MMF. Therefore, when different mixtures of adulterated honey are coated on the NC-MMF section, the peak wavelength changes according to the refractive index of the mixture. In this way, adulterated honey can be detected from the shift in wavelength of the transmission peak. The device was tested on a compliant commercial honey brand, exhibiting a linear response with a sensitivity of -0.5417 nm/% in the 1%-5% adulteration range.
TopIntroduction
Honey is a sweet, viscous substance produced by bees from the nectar of flowers or secretions from certain insects. It is a natural food product that has been used by humans for thousands of years (Zhang & Abdulla, 2022). Bees collect nectar from flowers and the enzymes present in the bee's stomach transform the nectar into honey through a process of regurgitation and evaporation. Once the bees return to the hive, they deposit the honey into wax cells and fan their wings to accelerate the drying process, resulting in the thick, syrupy consistency of honey (Bogdanov, 2012).
Honey is predominantly composed of carbohydrates, primarily fructose, and glucose, which give it its sweetness. It also contains trace amounts of minerals, vitamins, enzymes, antioxidants, and other bioactive compounds that contribute to its potential health benefits (Bogdanov et al., 2008). Has been traditionally used to treat laryngitis, as well as for its antimicrobial, antiviral, and antiparasitic properties. It has been used in traditional medicine and natural remedies for its potential healing, and in the cosmetic industry as an ingredient in skin and hair care products due to its moisturizing and antioxidant properties (Talha et al., 2023). Besides, honey is also used in the food industry as a natural sweetener in foods and beverages, a topping for desserts and breakfast items, or an ingredient in sauces and dressings (Bogdanov, 2012; Talha et al., 2023).
However, honey quality and authenticity pose a challenge due to adulteration. Honey adulteration refers to mixing or altering pure honey with other ingredients or substances to increase the quantity, improve its appearance, and flavor, or for more significant economic gain (Fakhlaei et al., 2020). The adulteration can be categorized into direct and indirect, as depicted in Figure 1. Direct adulteration involves adding a substance directly to the honey, while indirect adulteration happens when the honeybees are given a substance that adulterates the honey (Jaafar et al., 2020).
Figure 1. Honey adulteration categories
Typically, direct adulteration includes diluting honey with water, adding inexpensive sugars or syrups, mixing with lower quality or unknown-origin honey, or incorporating chemicals such as antibiotics or pesticides to prevent fermentation and prolong shelf life (Fakhlaei et al., 2020; Jaafar et al., 2020). In this sense, sugar addition is the main honey adulteration mechanism (Bogdanov, 2007) due to the use of cheaper and readily available sweeteners, such as cane sugar, beet sugar, glucose, fructose, sucrose, maltose, etc. (Oroian et al., 2018). Adulterated honey changes the biochemical and chemical properties and taste of honey, leading to a reduction in nutritional value and negatively affecting human health (Guler et al., 2014; Soares et al., 2017).
Detecting adulterated honey takes a significant role in the food industry. To address this need, several techniques/methods have been developed for its detection, such as spectroscopy (Mantha et al., 2018), stable carbon analysis (Cinar et al., 2014), chromatography (Wang et al., 2014), and Fourier transforms (FT) Raman spectroscopy (Batsoulis et al., 2005). Although these techniques are effective, they require adequate laboratory instruments, do not provide real-time measurements, and are expensive.