Physicochemical, antioxidant, volatile component, and mass spectrometry-based electronic nose analyses differentiated unrefined non-centrifugal cane, palm, and coconut sugars

Abstract

Unrefined non-centrifugal sugars in Southeast Asia emanate from various plant sources including sugarcane, palm, and coconut. To assess food and flavor characteristic differences of these unrefined sugars, seven cane, three palm, and two coconut sugars were evaluated in term of their physicochemical, antioxidant, and volatile flavor properties. Results indicated that unrefined sugars from cane had significantly higher ICUMSA color value than palm and coconut sugars, yet they possessed comparable total soluble solid levels. Cane sugars also presented superior phenolic and flavonoid contents and antioxidant activities, particularly in Thai and Japanese products. Each sugar had distinct volatile flavor composition, comprising acids, Maillard reaction products (furanone, pyrazine, furan, and pyrrole), aldehydes, alcohols, and sulfurs. All traditionally made unrefined sugars had significantly greater Maillard reaction products and less acetic acid than in industrially manufactured cane sugars. Then, propanoic acid and [R-(R*,R*)]-2,3-butanediol were solely major volatiles in palm sugars from Thailand. Additionally, mass spectrometry-based electronic-nose (e-nose) profiling detection provided specific ion masses from various volatile components as potential chemical markers in monitoring aroma characteristic of unrefined sugars and differentiated these sugars into nine statistical clusters based on their materials and origins, wherein palm sugars from Thailand and Indonesia, as well as cane sugars from Thailand and Japan, had comparable volatile profiles.