Effects of calcium citrate, chitosan and chitooligosaccharide addition on acrylamide and 5-hydroxymethylfurfural formation in dark brown sugar

Calcium citrate, chitosan, and chitooligosaccharide were added to sugarcane juice to investigate their effect on color, pH, antioxidant activity, reducing sugar, acrylamide and HMF mitigation in dark brown sugar production. Results showed that the content of 52–67% acrylamide in the dark brown sugar was mitigated with 0.1–1.0% chitosan addition and the reducing power of dark brown sugar increased with 0.5–1.0% chitosan addition. Furthermore, the addition of 0.5–1.0% chitosan or chitooligosaccharide increased HMF formation. Only the pH of dark brown sugar with chitosan addition was lower than that of other dark brown sugars. This is due to the low pH condition in dark brown sugar mitigating Maillard reaction and acrylamide formation. When the pH of sugarcane juice with chitosan adjusted back to pH 7 again, the acrylamide content of dark brown sugars significant increased (p < 0.05). Acrylamide and HMF are both produced through the Maillard reaction, the lower pH will cause the hydrolysis of sucrose to produce more HMF and reducing sugar. The L values and white index of dark brown sugar with 0.5–1.0% added chitosan were lower than those of control dark brown sugar (p < 0.05). High negative correlation was observed between HMF and acrylamide in the present study.