Quantitative viscosity determination in irradiated major spices (black pepper, cardamom, cinnamon, ginger, and turmeric) by using a vibro viscometer for long-term storage

Abstract

The overall purpose of the study was the quantitative determination and identification of irradiated (0, 5, 10, 15 and 20 kGy) black pepper, cardamom, cinnamon, ginger, and turmeric aqueous suspensions with regards to viscosity changes just after irradiation and during long-term storage. Enzymatic starch analyses (GOPOD) results confirmed that spice samples (black pepper, cardamom, cinnamon, ginger, and turmeric) have high starch content (43.6–63.8%) except for cinnamon (10.5–12.0%). The measured viscosity values (mPa.s) of the samples (black pepper, cardamom, cinnamon, and ginger) significantly decreased with increasing absorbed irradiation doses (up to 15 kGy) during storage ( p < 0.05). When the different irradiation doses were compared, it was clear that the doses of 5 and 10 kGy caused a dramatic decrease in viscosity values. Cardamom, black pepper, and ginger samples were irradiated at a dose range of 5–20 kGy, which could be detected even after 18 months. In contrast, it has been found to give positive results in storage up to 12 months for turmeric and cinnamon samples as a detection method. It is still possible to identify irradiated black pepper, cardamom, cinnamon, ginger, and turmeric even after months of storage. Furthermore, the vibro viscometer provided rapid, precise, and reliable results and it was a user-friendly instrument for detection of irradiated spices. • Long-term storage (18 months) tests were performed on irradiated spice viscosity. • Viscosity showed a significant ( p < 0.05) decrease with respect to dose. • Irradiated black pepper, cardamom and ginger samples were detected after 18 months. • Cinnamon and turmeric samples gave positive results in storage for up to 12 months. • The vibro viscometer provided rapid, precise, and reliable results for spices.