Pectin methyl esterase treatment on high-methoxy pectin for making fruit jam with reduced sugar content.
BACKGROUND
Pectin methyl esterase (PME) has been postulated to catalyse the transacylation reaction between pectin molecules. The present study aimed to prove the occurrence of this reaction. The feasibility of applying PME-catalysed transacylation between high-methoxy pectin molecules in making fruit jam with reduced sugar content was also investigated.


RESULTS
PME treatment increased the turbidity and particle size in pectin solution and the molecular weight of pectin, while it decreased the number of methoxy ester linkages and the intensity of the CH₃ absorption peak in the Fourier transform infrared spectrum without changes in the number of total ester linkages in pectin molecules. These findings support the occurrence of PME-catalysed transacylation between pectin molecules. Higher values of hardness, gumminess and chewiness were found in a jam containing PME-treated citrus pectin (10 g L⁻¹) and sugar (350 g L⁻¹) as compared with either a jam containing untreated citrus pectin (10 g L⁻¹) and sugar (350 g L⁻¹) or strawberry jam containing pectin (10 g L⁻¹) from the fruit and sugar (650 g L⁻¹).


CONCLUSIONS
The demand for sugar in jam making can be greatly reduced by the use of PME-treated high-methoxy pectin.
Life Science Center, Hsing Wu Institute of Technology, Taipei 244, Taiwan.
Yuh-Tai
YT
Wang
Ling-Lan
LL
Lien
Ya-Chu
YC
Chang
James Swi-Bea
JS
Wu
D000215:Acylation; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D055598:Chemical Phenomena; D032084:Citrus sinensis / Q000737:chemistry; D003212:Condiments / Q000032:analysis*; D050528:Diet, Carbohydrate-Restricted; D004038:Diet, Reducing; D019422:Dietary Sucrose / Q000032:analysis*; D005240:Feasibility Studies; D005511:Food Handling; D031985:Fragaria / Q000737:chemistry; D005638:Fruit / Q000737:chemistry*; D006801:Humans; D006868:Hydrolysis; D055595:Mechanical Phenomena; D008745:Methylation; D008970:Molecular Weight; D010368:Pectins / Q000737:chemistry / Q000378:metabolism*; D017673:Sodium Chloride, Dietary; D013624:Taiwan
D019422:Dietary Sucrose; D017673:Sodium Chloride, Dietary; D010368:Pectins; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase