Effects of hydrocolloids on the bakingproperties of the litchi jam

In this paper,thealginate and low methoxyl( LM) pectin were used as additives,the effects of the ratio between alginate and LMpectin,p H and calcium concentration on the baking properties of the litchi jam were discussed.The rheological properties and aroma compounds of the pre and post- baking jam were studied by the rheometer and gas chromatography- mass spectrometer.The results indicated that with the ratio between alginate and LMpectin( 6 /4),a narrower p H range( 3.6~3.8) and a broader calcium tolerance( 30 mg Ca / g hydrocolloids)the post- baking jam illustrated the high RBS and RFS( ≥90%) and the low syneresis( ≤1%). The results also showed that pre and post- baking jam were both yield- pseudoplastic fluid andtheir flow curve which had a good correlation with the Herschel- Bulkley model.In the frequencyregion,the G' was higher than G″ of the post- baking jam leading to the mixed systemdominated by elastic,showing the typical“weak gel”properties.After baking,the contents of alkene and alcohols were greatly increased by 12% and 9% respectively,while the content of aldehydes and alkane were decreased.As a result,the baking properties of the litchi jam were enhanced by adding the alginate and LMpectin.