Impact of Thermal Processing on the Composition of Curcuma longa Rhizome

Abstract

Curcuma longa L. (Zingiberaceae), known as turmeric, is a perennial tuberous plant from the genus Curcuma, which includes about 100 plant species. The chemical composition of the turmeric rhizome is very diverse. Diarylheptanoid derivatives, also known as curcuminoids (of which curcumin, demethoxycurcumin and bisdemethoxycurcumin are the most important representatives), are the major active constituents of the plant rhizome. Many extracts used in the food and pharmaceutical industries are produced from thermally processed rhizome, when there are significant changes in the composition of the main compounds. Therefore, the aim of the study was to compare how the type of thermal treatment affects the content of curcuminoids and the antioxidant properties of the rhizome. The plant material was subjected to three different methods of thermal processing—microwave heating, boiling and frying in different time intervals. The chemical composition and antioxidant activity of the processed rhizome was evaluated using LC-MS (liquid chromatography–mass spectrometry), HPLC (high-performance liquid chromatography) and spectrophotometric methods (a DPPH test and TPC assay). Obtained results revealed that curcumin was the major curcuminoid present in all samples (113.92 mg/g of the fresh rhizome). Significant correlation between the type and time of the thermal processing and the composition of turmeric samples was revealed. A traditional boiling process lasting for 10 min was the most beneficial process in terms of the curcuminoid content (204 mg/g of curcumin) and antioxidant activity of the samples.

Analysis of antioxidant potential and study of the features of the microstructure in certain types of spices and herbs used in the meat processing industry

“…As can be seen from the obtained data, none of the samples showed a positive result for carotenoids. However, many studies have confirmed the high carotene content in turmeric [42], also red pepper is a rich source of bright representatives of carotenoids -lutein, carotene and capsanthin [43]. This indicates the inapplicability of this method of qualitative analysis to these extracts.…”

Influence of Thermal Treatment on the Composition of Alpinia officinarum Rhizome

“…In the case of the turmeric rhizome and its major active compounds, called curcuminoids, the boiling and frying process resulted in an increase in the content of these compounds (curcumin content: from 114 for the fresh rhizome to 204 mg/g after 10 min of boiling and to 224 mg/g after 10 min of frying). In the case of microwave heating, the trend was opposite-there was a decrease to 36 mg/g after 5 min [105]. The decrease in the antioxidant activity with an increase in temperature may result from ongoing processes and reactions leading to the formation of new substances with lower antioxidant activity compared to compounds present in the unprocessed raw material (for example, the formation of shogaols from gingerols in the case of ginger rhizome) [106].…”

Chemical Composition of Turmeric (Curcuma longa L.) Ethanol Extract and Its Antimicrobial Activities and Free Radical Scavenging Capacities

“…More recently, the growing interest in the relationship between diet and health has elevated the importance of using spices in the food arena and understanding the mechanisms behind their beneficial properties [1]. Turmeric (Curcuma longa L.) is a perennial tuberous plant from the genus Curcuma (Zingiberaceae) and is commonly distributed in East, South, and Southeast Asia [2]. The rhizomes of turmeric are well-developed, clumped, branching, elliptic, or cylindrical and are widely used in many foods, such as canned beverages, baked products, dairy products, ice cream, yogurt, yellow cakes, milk, orange juice, biscuits, popcorn, cereals, sauces, and others, in the form of powder for over 4000 years [3,4].…”