Comparative Study On Nutritional Composition And Flavor Substances Of Different Brown Sugars

Brown sugar is a non-centrifugal sugar formed by fresh sugar cane after juicing,boiling,concentrating and crystallizing,which is rich in minerals,amino acids,proteins and other nutrients.As an important traditional health food in China,brown sugar has the effects of beautifying skin,tonifying spleen,warming stomach and promoting body metabolism.Brown sugar has become a necessity in people’s daily life,and its quality is emphasized by consumers.The nutritional composition,flavor substances and antioxidant properties are important indicators for evaluating the quality of brown sugar,while those indicators of brown sugar from different sugarcane varieties,different technology and commercial brown sugar have not been systematically studied.In this study,nutritional composition,flavor substances and antioxidant properties of brown sugar from different sugarcane varieties,different technology and commercial brown sugar were compared.The main results are as follows:1.Five sugarcane varieties mainly planted in Yulin,Guangxi: Zhongtang-3,Guitang-44,Guitang-55,Liucheng-05-136 and Roc-22 were selected as raw materials to prepare brown sugar in the traditional way,and to compare the differences in nutrients,flavor substances and antioxidant activity of the brown sugar samples they made.The results showed that brown sugars from Guitang-55 and Zhongtang-3 have the richest nutrients,and the former has the highest total free amino acids content,while the latter has the highest sucrose,total polyphenol and Fe contents as well as richer aroma components and the strongest antioxidant capacity.Brown sugar from Guitang-44 has the highest protein content,and those from Liucheng-05-136 and Roc-22 have moderate nutrients and aroma components contents as well as antioxidant activities.This study may provide a theoretical basis for the selection of sugarcane varieties for the production of functional brown sugar.2.Brown sugars from sugarcane of Zhongtang 1 under the sugarcane base in Lingao,Hainan was selected as the raw material,and a comparative study was conducted on the nutritional composition,flavor substances and antioxidant properties of the brown sugar samples.The results indicated that there are significant differences(P < 0.05)in the contents of ash,fat,sucrose and total polyphenols in the two brown sugar samples,while there are no obvious differences(P > 0.05)in the contents of moisture and protein.The two samples have the same amino acid types but different amino acid contents,with higher contents in the machine-made sample.Except Na,contents of P,Fe,K,Ca,Mg and Mn were significantly different between the two brown sugar samples(P < 0.05).Forty-five aroma substances were detected in the two samples,and handmade brown sugar was richer in aroma components.Both samples have antioxidant properties,and machine-made brown sugar has higher scavenging power of DPPH free radicals but slightly lower power for hydroxyl radicals.3.Eight kinds of commercial brown sugar from the main sugarcane planting areas in Yunnan,Guangxi,Fujian,Guangdong and other major brown sugar producing provinces were obtained as samples,and a comparative study on the quality of them in terms of nutrient compositions,flavor substances and antioxidant properties was conducted.The results are demonstrated as follows.In terms of nutritional indexes,ash and protein contents of the samples have no significantly difference(P > 0.05),while their moisture,fat,sucrose and total polyphenol contents differs significantly(P < 0.05),with the highest moisture content in No.2,the highest fat content in No.1,the highest sucrose content in No.4,much higher total polyphenol and ash contents of No.7,as well as the highest protein content in No.8.Significant differences(P < 0.05)were found among the elements P,Fe,K,Ca and Mn in the samples,except Na and Mg,and the highest total mineral element content was found in brown sugar No.7.A total of65 volatile aroma substances were detected in the 8 samples,among which types and contents of aldehyde and pyrazine are richer than other constituents.N-octanal,2-methylpyrazine and2,6-dimethylpyrazine exist in all samples,and No.7 had the most abundant aroma compounds;The brown sugars all showed the ability to scavenge DPPH free radicals and hydroxyl radicals,and their abilities are positively correlated with their concentration,but lower than those of Vc,No.8 brown sugar has the strongest free radical scavenging ability,while No.7 brown sugar is the most nutritious and has the best health effects.