Glucose syrup production through enzymatic methods and acid hydrolysis using different starch sources: a systematic review

Glucose syrup is a clear and viscous liquid often produced using starch that is subjected to acid hydrolysis or enzymatic methods. Therefore, this review aimed to evaluate the potential starch sources to produce glucose syrup using these two methods. The data used were articles retrieved from Scopus and Google Scholar databases based on relevant keywords. The search was conducted by limiting the articles to only English-language journals published between 2013 and 2023. The results show that the starch sources capable of being hydrolyzed into glucose syrup using either enzymatic or acid hydrolysis include sago, cassava, wheat, corn, potato, taro, sorghum, jicama, sweet potato, and rice. The enzymatic method was proven to be more effective in producing high returns compared to acid hydrolysis. Moreover, the key factors to be considered in the process included catalyst concentration which was found to be optimal at 0.02% α-amylase and glucoamylase for enzymatic methods and 150 ml 0.1 M/50 g starch for acid hydrolysis. Another factor was incubation time was observed to be optimal at 2 h for liquefaction and 48 h for saccharification in enzymatic methods but 13 h for acid hydrolysis. Furthermore, the best incubation temperature was reported to be 95 °C for liquefaction and 60 °C for saccharification in enzymatic methods but 95 °C for acid hydrolysis. The results also showed that the optimal pH was 6–6.2 for liquefaction and 4–4.2 for saccharification in enzymatic methods but 1–2 for acid hydrolysis. It was also reported that corn produced the highest yield compared to other materials. The review provided a comprehensive and holistic overview of glucose syrup production from several types of starch and two different methods.