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Purpose of this study was to develop prototype cooking equipment that can work at reduced pressure and to evaluate its performance for production of strawberry jam. The effect of vacuum cooking conditions on color soluble solid content, reducing sugars total sugars HMF and sensory properties were investigated. Also, the optimum vacuum cooking conditions for strawberry jam were optimized for Composite Rotatable Design. The optimum cooking temperature and time were determined targeting maximum soluble solid content and sensory attributes (consistency) and minimum Hue value and HMF content. The optimum vacuum cooking conditions determined were 74.4 °C temperature and 19.8 time. The soluble solid content strawberry jam made by vacuum process were similar to those prepared by traditional method. HMF contents of jams produced with vacuum cooking method were well within limit of standards.

Herein we report a comparison study of the quality characteristics of tomato paste produced under atmospheric conditions and vacuum evaporation. Tomato pulp (5 Brix) was evaporated under vacuum and at atmospheric pressure using a developed evaporation equipment for household application. Various quality i.e. a* and a*/b* color values, soluble solids content, dark speck amount, titratable acidity, lycopene content and sensory properties of tomato paste were compared. The fi nal total soluble solid contents were not affected by evaporation method whereas the lycopene content in vacuum evaporated samples was found as higher than that in the atmospheric ones at the same soluble solid content. Overall preference scores of vacuum evaporated tomato paste have approximately equal scores with the paste produced at atmospheric conditions.

Vacuum frying conditions were investigated with respect to physical, chemical and sensorial properties of French fries and frying oil, besides determining the effect of frying conditions in terms of frying temperature and time. In order to determine the optimum frying conditions of the French fries optimization study was carried out according to Central Composite Rotatable Design. The results were evaluated to determine optimum vacuum frying conditions targeting minimum oil content, 30–45 N in range of hardness, minimum acrylamide content and maximum overall preference. The optimum vacuum frying condition was selected as 124.39 °C of frying temperature and 8.36 min of frying time for French fries. The French fries obtained at optimum conditions for vacuum frying preserved the desired color, textural properties and flavor and it has low oil content and reduced acrylamide formation. In addition, the frying oil quality was preserved with vacuum frying.