Dadih is a favourable dessert in South East Asia due to its appealing sweet taste and jellies
appearance. The sweet taste is from sugar (sucrose) content, and in order to reduce the sucrose,
it was substituted with xylitol. Xylitol can provides intense sweetness with less calories and
lower water activity, which potentially contribute to higher microbial stability thus giving
longer shelf life. The objective of this study was to evaluate the effect of xylitol substituted
on dadih safety and sensory qualities. Dadih was prepared by replacing sucrose with xylitol
composition in the range of 0 – 100% and at two levels of cooking times (15 and 20 minutes).
Safety analysis were performed using total plate count (TPC) and water activity (aw) analysis.
For sensory analysis, seven attributes were evaluated (appearance, colour, hardness, elasticity,
taste, sweetness, and overall acceptability) based on the 9-hedonic scale. From the findings,
dadih samples with total sucrose (0%) were observed to be contaminated faster compared to
total xylitol (100%). Dadih with xylitol is more stable with prolonged shelf life. From sensory
analysis, dadih sample prepared with shorter cooking time (15 minutes) was selected as more
favourable with overall acceptability score between 72 - 85%. More than 70% of the score for
dadih with xylitol substitute was above ‘slightly like’, which indicates a promising future to
produce xylitol substitute dadih. The outcome of this study has shown that xylitol is potentially
to be utilize as sugar substitute for dadih production.
Subcritical water hydrolysis process for sugar recovery from leftover croissants (LC) and leftover doughnuts (LD) was optimised using response surface methodology with three process parameters as dependent variables and sugar yield as the response. The process parameters: temperature (160-200 °C), time (5-15 min), and solid loading (10-50%), on the sugar yield were investigated. For the LC sample, the optimised process conditions were determined to be: 200 °C, 6.17 min, and 10% solid loading producing an 80% hydrolysis yield of 466.11 ± 0.67 mg/g. Comparatively, the LD sample optimisation parameters were: 200 °C, 5 min, and 10% solid loading producing a 76.18% hydrolysis yield of 394.34 ± 0.33 mg/g. The sugar extracts were further characterise; which through scanning electron microscopy revealed the LC had most starch granules rupture during hydrolysis, while Fourier-transform infrared spectroscopy detected the presence of monosaccharides and oligosaccharides for both LC and LD. 5-hydroxymethylfurfural (5-HMF), a sugar degradation by-product, was also detected with 39.16 ± 0.61 and 20.59 ± 0.81 mg/g for the LC and LD, respectively, at optimal conditions.