Red Raspberry Jelly
Trehalose can be used in jams and jellies to improve the flavor profile by decreasing sweetness slightly and enhancing overall fruit flavor. Trehalose is stable to low pH and high process temperatures, conditions which typically produce caramelized off-notes with other sugar systems.
The following laboratory-scale formulation is a red raspberry jelly containing a 30% reduction in corn syrup solids:
| Red raspberry juice concentrate (Gillette Flavors) | 4.0% |
| Water | 16.9% |
| Trehalose | 16.8% |
| Isoclear® 42 HFCS | 33.6% |
| Clearsweet® 43/43 corn syrup | 19.7% |
| Pectin (liquid) | 6.8% |
| Cargill Citric Acid, Anhydrous | 0.2% |
- Thoroughly mix the juice concentrate, sugars, and water. Process to boiling, stirring occasionally.
- Add the pectin and process to boiling for one minute.
- Remove from heat and stir in the citric acid.
- Pour into sterilized jars, cover with lids and save.
- Invert for five minutes, then turn upright.
Dried Fruit Powders
The color and flavor of dried fruit powders can be improved with the addition of trehalose. The acid stability and non-reducing properties of trehalose do not promote caramelization or browning during the drying process. These properties combined with reduced sweetness allow the natural color and flavor of the fruits to be preserved. The following application is for the preparation of dried strawberry powder.
| Strawberries | 94.5% |
| Trehalose | 5.5% |
- Puree strawberries with the addition of 5.5% dry solids trehalose.
- Pour into a shallow metal pan and dry at 50º C for 20-24 hours in a forced air oven.
Caramel
Trehalose can be used in caramels to improve both texture and flavor profiles. The texture is improved by increasing firmness and reducing stickiness. These textural benefits are complemented by a slight decrease in sweetness, which allows caramel flavor notes to be intensified.
The following formulation for cut and wrap caramel contains 10% trehalose as part of the dry sweetener solids system.
| Clearsweet® 43/43 corn syrup | 44.85% |
| Isoclear® 42 HFCS | 28.55% |
| Trehalose | 6.90% |
| Evaporated milk | 13.15% |
| Coconut oil (92 oF m.p.) | 4.50% |
| Salt | 0.05% |
| Disodium phosphate | 0.10% |
| Water | 1.90% |
- Dissolve the disodium phosphate in the evaporated milk.
- Combine all ingredients and cook over direct heat to 240-245º F.
- Cook to 93% solids.
- Cool, cut, and wrap.
Hard Candy Model System
The reported glass transition temperature, T0 (dry), for trehalose is 79º C. This value is high as compared to 52º C for sucrose. The higher the Tg value, the more stable an amorphous (glass) system should be. Hard candy is an amorphous sugar system - a low moisture (1-2%) melt of sucrose, corn sweeteners, acid and flavor. By partial to full replacement of sucrose using trehalose, hard candy can be more stable to moisture gain and sugar recrystallization upon storage.
The following hard candy model system contains trehalose as a full replacement for sucrose:
| Trehalose | 49.1% |
| Clearsweet® 43 High Maltose Corn Syrup | 5.5% |
| Water | 14.6% |
- Combine all ingredients and cook over direct heat to 98% dry solids.
- Deposit into Teflon coated molds to set.
Glass Stability of Trehalose Using a Hard Candy Model System
Experimental Objective:
The reported glass transition temperature, Tg (dry), for trehalose is 79 ºC. This value is high as compared to 52 ºC for sucrose. The higher the Tg value, the more stable an amorphous (glass) system should be. Hard candy is an amorphous sugar system - a low moisture (1-2%) melt of sucrose, corn sweeteners, acid and flavor. The objective of this experiment was to study the potential increase in the Tg value in a hard candy model system made with an increasing amount of trehalose replacing sucrose and the effect on stability (hygroscopicity and sugar recrystallization).
Method:
The following systems were prepared:
Each system was cooked over direct heat to 98% solids. The systems were deposited into Teflon coated molds to set. When set, the hard candies were placed in 43%, 54%, and 75% relative humidity (%R.H.) chambers. Weight measurements were taken until equilibrium was reached.
Results:
Final product moisture and Tg values were run on all candy systems.
At 43% R.H., all candies tested were stable to moisture gain. The control candy did, however, appear to have a slight level of crystals forming near the end of the equilibration period (3 weeks). This was not unexpected considering the Tg for the control candy was lower than for the 20% and 40% replacement systems. The higher the Tg value, the more viscous the system and the longer it will take for sugar recrystallization.
At 54% R.H., the samples gained moisture. The control system had crystallized sugar as early as day 3 of the experiment. The 20% and 40% replacement systems also had crystallized sugar, but to a much lesser extent than the control. The 60% replacement system did not show any sugar recrystallization. The control and the 20-60% replacement systems exhibited cold flow toward the end of the equilibration period, with higher trehalose replacement having less cold flow. The 100% sucrose replacement system crystallized quickly, but the crystallized sugar appeared as a thin coat around the candy pieces - this system did not exhibit cold flow.
At 75% R.H., the control and the 20-60% replacement systems gained a great deal of moisture and lost their molded shape. The 100% replacement system gained comparatively less moisture, and did not deform - its shape remained intact.
Conclusions:
Trehalose additions to hard candy glasses were shown to decrease the rate of sucrose recrystallization, a common problem with hard candy during storage. Additions may also inhibit "cold flow" issues
(as seen for the 100% replacement system) where some degree of crystallization can be tolerated.
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