Dr. Dakshayani.R and G. Pavithra
Independent Researcher, Thanjavur
This article provides an overview of the issue of spices adulteration and the various techniques used for detecting adulterants in spices
Spices hold significant value as export-driven goods, finding wide applications in flavouring food, beverages, medicine, and cosmetics. These commodities could be traded in various forms such as dried or fresh whole products, powders, pastes, dehydrated materials, oils, oleoresin, and extracts. The export value of spices from India has continued its upward trend during 2020-2021 and has attained an all-time high of UD $4.0 billion mark for the first time in the history of spice export owing to the pandemic. The superior quality of spices plays a vital role in their perceived biological effectiveness, flavour, and aroma. There’s a growing global demand, particularly from health-conscious consumers, seeking high-quality spices for their health, culinary or cosUnfortunately, the authenticity of spices is often compromised through adulteration with inferior substances resembling them, which diminishes their perceived biological worth and erodes public trust in these products.
Table 1: Spices and adulteration
|Black pepper||Papaya seeds|
|Turmeric powder||Lead chromate metal yellow|
|Chilli powder||Brick powder|
|Asafoetida (Hing)||Foreign resin|
Detection techniques – Simple
Asafoetida: The asafoetida was taken in a stainless steel spoon and burnt. Pure asafetida burns like camphor whereas adulterated does not provide bright flames like camphor.
Papaya seeds: The black pepper was poured in a glass of water. The purest papaya seeds only settle at the bottom whereas the adulterated papaya seeds float on the surface of the water.
Cloves: When cloves were put into a glass of water, the original one settled at the bottom, whereas the exhausted (de-oiled) one floated on the surface.
Cinnamon: On examining a small quantity of cinnamon on a glass plate, cinnamon barks were found to be very thin, rolled around like a pencil or pen, whereas cassia bark had several layers in between the rough outer and inner most smooth layers.
Cumin seeds: A small quantity of cumin seeds, when rubbed on palms and turned black, indicate they are adulterated with charcoal dust.
Turmeric whole: When turmeric is placed in a transparent glass of water and doesn’t change in colour, it is pure. When the colour of water changes immediately, it indicates that turmeric was adulterated with lead chromate.
Advanced Detection Techniques
The modern technologies used to find adulteration in spices and to meet the export quality of spices and are described below:
High-Performance Liquid Chromatography (HPLC): It is instrumental in isolating, identifying, and quantifying individual components in mixtures, making it effective for adulterant or contaminant detection in spices.
Gas Chromatography- Mass Spectrometry (GC-MS): It is used to separate and analyse the complex mixtures of compounds. Highly effective in identifying volatile compounds and could be used to detect adulterants or contaminants in spices by analyzing their chemical profiles.
Nuclear Magnetic Resonance Spectroscopy (NMR) : It provides detailed information about the molecular composition and structure of substances. It is utilized to detect and quantify adulterants in spices by comparing the NMR spectra of authentic and potentially adulterated spices.
Near-Infrared Spectroscopy, Fourier-Transform Infrared Spectroscopy : It is used for analysing the absorption of infrared light in near and far region by the molecules in the samples. It was found to be an effective and non-destructive technique with rapid detection in the composition of spices by detecting adulterants in unique spectral characteristics.
Electronic nose, Ion chromatography, and Isotope Ratio Mass Spectrometry (IRMS) were also other chromatographic techniques.
Electrophoretic method : Electrokinetic separation in capillary electrophoresis effectively assesses compound purity and complexity through charged component detection by application of high voltage, the idea for quality control of the saffron spice trade.
Biotechnological methods : The biotechnological methods adopted were the Polymerized Chain Reaction (PCR) method, hybridization method, and DNA sequencing method.
PCR based method: It involves species-specific primer amplification, random amplified polymorphic DNA, arbitrarily primed, DNA amplification fingerprinting, inter simple sequence repeat (ISSR) etc. It focuses on amplification of micro-satellite regions/DNA in the genome, yield a unique pattern for an individual and helps in authentication and adulteration of spices.
Hybridization based method: Hybridization works on the generation of species-specific DNA profiled by hybridizing DNA digested with restriction enzymes and comparing with labelled probes. The techniques were restriction fragment length polymorphism (RFLP), variable number tandem repeat (VNTR), and microarray techniques.
DNA Sequencing method: It involves identifying species by analyzing DNA sequences. This technique could detect adulteration by identifying DNA from unexpected or undesired sources in spice samples. The integration of traceability and authentication method, with quality standards, facilitate the legitimate trade of spices.
Spices fetches high value, export-oriented features widely in flavouring food and beverages. The adulteration in value added commodity of spices was found to be difficult by visual aids. Thus, simple method of detecting spice adulteration was given by FSSAI. Simple detection methods for spice adulteration, however, have certain drawbacks when compared with advanced detection methods. The major disadvantages of simple detection methods were Accuracy, sensitivity, specificity, limited parameters, complex adulterations, and quantitative analysis. Thus, advanced techniques emerge and result in rapid detection of adulterants in spices.
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Modupalli, N., Naik, M., Sunil, C. K., & Natarajan, V. (2021). Emerging non-destructive methods for quality and safety monitoring of spices. Trends in Food Science & Technology, 108, 133-147.
Sasikumar, B., Swetha, V. P., Parvathy, V. A., & Sheeja, T. E. (2016). Advances in adulteration and authenticity testing of herbs and spices. In Advances in food authenticity testing (pp. 585-624). Woodhead Publishing.
About the Authors:
III year, B.Sc (Hons) Agriculture, Anbil Dharmalingam Agriculture College and Research Institute, Dindigul Main Rd, Muthukulam, Navalurkottapattu, Tamil Nadu