This study aimed to investigate the effect of storage temperature and pressure plate treatment on chemical composition in Prunus mume sugar extracts (PSEs). Green Prunus mume fruit was mixed with an equal amount of commercial sugar and stored at 4 or 25oC for 9 mon with or without a pressure plate. The alcohol contents in PSEs stored at 4oC were lower than those stored at 25oC. The amygdalin contents in PSEs stored at 25oC with pressure plate were significantly low. The sucrose in PSEs was converted into glucose and fructose during storage. The glucose, fructose and total phenol contents in PSEs stored at 25oC were higher compared with those at 4oC. The total soluble solid and polyphenol contents in PSEs were increased at 25oC until 90 d and 4oC until 150 d and then the contents were constant. The total acidity in PSEs stored at 4oC were higher than those at 25oC. These results indicate that storage temperature plays an important role in controlling the alcohol, amygdalin and sucrose contents in Prunus mume sugar extracts (PSEs).

This study was conducted to investigate changes on the quality characteristics of Prunus davidiana sugar extracts (PSEs) by processing conditions. The PSEs were prepared by extraction with commercial sucrose at 4°C or 25°C for 9 months with or without a pressure plate. The quality characteristics of PSEs were analyzed for Bxo, pH, total acidity, Hunter color value, alcohol content, polyphenol content, DPPH radical scaveging activity, and free sugar content. Bxo increased significantly while pH decreased with increased storage period (p<0.05). The PSEs stored at 4oC scored lower than those stored at 25oC for total acidity, alcohol content, and polyphenol contents. The PSEs with pressure plate possessed lower alcohol content and higher polyphenol content and DPPH free radical scavenging activity than those without pressure plate. The sucrose content in PSEs decreased with increased storage period, while glucose and fructose contents increased. These results indicate that by increasing storage period, sucrose in PSEs is decomposed into glucose and fructose, and the quality characteristics of PSEs such as total acidity, alcohol, and polyphenol content depend on processing conditions.

The purpose of this study was to optimize the mandarin dry chip manufacturing using a response surface methodology. The experiment was designed based on a CCD (Central Composite Design), and the independent variables were the drying temperature (X1, 50-90oC), drying time (X2, 12-36 hours), and microwave pretreat time (X3, 0-4 minutes). The results of appearance (Y5), color (Y6), taste (Y8) and overall acceptance (Y10) were fitted to the response surface methodology model (R2=0.86, 0.88, 0.89, and 0.84, respectively). Increasing the drying temperature and microwave treatment time were negatively evaluated for consumer acceptance. On the other hand, a high value of consumer acceptance was evaluated when the drying time was more than 24 hr. Therefore, the optimal conditions of X1, X2, and X3 were 52.989oC, 24 hr, and 1 min, respectively. Under these optimal conditions, the predicted values of Y5, Y6, Y8, and Y10 were 5.066, 5.338, 5.063, and 5.339, respectively.

The purpose of this study was to develop a peach spread premix to increase the usability of peaches with low storage stability. We analyzed the effect of adding different ratio of peach powder (0, 5, 10, 15%) on the physicochemical and sensory quality characteristics of peach spread premix. The result showed that the pH of the spread premix significantly decreased with the addition of greater amounts of peach powder (p<0.05). The total titratable acidity (TTA) and sweetness of the peach spread premix were significantly increased as the amount of added peach powder increased (p<0.05). The redness (a-value) and yellowness (b-value) increased with an increase of the peach powder ratio; however, the lightness (Lvalue) decreased (p<0.05). The water activity and viscosity of the spread decreased with an increased amount of added peach powder. The results of the sensory test with spread premix prepared with 10% peach powder had the highest score for color, taste, texture, stickiness, and overall acceptability (p<0.05). We suggested that the peach spread premix made with 10% peach powder may be the most desirable for manufacturing spread premix and for improving sensory preference.

This study was conducted to investigate the quality characteristics of peach jelly following the addition of various gelling agents (locust bean gum, carrageenan, xanthan gum). The various gelling agents were added to peach jelly at five levels (1.0, 1.5, 2.0, 2.5 and 3.0%), after which their effects on physicochemical properties, textural properties and sensory qualities were investigated. The total titratable acidity (TTA) of peach jelly was decreased with increases in gelling agent. Additionally, the sweetness and pH of peach jelly increased significantly as the amount of various gelling agents increased. Moreover, the lightness (L-value), redness (a-value) and yellowness (b-value) of peach jelly was decreased as the amount of gelling agent. Furthermore, the hardness, gumminess and chewiness of the peach jelly increased as the amount of gelling agent increased. Finally, the overall acceptance was higher for jelly containing 2.0% added gelling agent than for other samples. Based on the results of this study, it is recommended that mixed gelling agents be added to peach jelly at 2.0%.