Effect of Incubation, Enzymes and Thermal Pre-treatments on the Quality of Pumpkin Juice

Hesham Ae Manal Fs

doi:10.4172/2155-9600.1000371

Abstract

Incubating fresh pumpkin (Cucurbita pepo L.) vegetable slices treated with thermal pre-treatments and a commercial exogenous enzyme preparation cellulase and α-amylase produced a pumpkin juice. HPLC was also carried out to fractionate the major sugar component found in fresh and treated pumpkin juice. Sucrose was the major sugar of the pumpkin juice which hydrolysis during water and steam blanching and cellulase enzyme pretreatments to glucose and fructose. Results concluded that the incubated pumpkin have the lowest WIS and water content compared to the fresh pumpkin juice without treatment. No pectin-methyl-esterase (PME) activity was found in water, steam and enzymes pre-treatments of pumpkin juice compared with the fresh pumpkin juice without treatment. It was found that the yield was increased in water blanching, followed by cellulase addition and then steam blanching. The inhibitory effect of various thermal and enzymes pre-treatments based on a*-values measurements at their high time and maximum concentrations for pumpkin juice treated in the following decrease order steam blanching > microwave > water blanching > α-amylase enzyme > cellulase enzyme. This research proved that pumpkin can be used as a pumpkin juice with thermal and enzymes pre-treatments after incubated fresh pumpkin vegetable slices at 55°C for 3 hours.

Highlights

In the last ten years, there has been a great increase in the international consumption of tropical vegetable juices, including pumpkin, according to FAO (Food and Drug Administration. 1989)
Ella Missang et al, [18] and Massiot et al, [19] found that the enzymatic treatment of the apple tissues was more effective the longer the storage; yields correlated well with the enzyme hydrolysis of WIS). They found that the water insoluble solids (WIS) preparation was preferred to alcohol insoluble solid (AIS) preparation because (1) the endogenous enzymes should act as they did in the crushed apple pulp and (2) the cell wall polysaccharides were more accessible to exogenous enzymes in the WIS than in the AIS material
The water content of the pumpkin tissue decreased with a losses 3% in different incubation temperatures during the 24 hours incubation period

Summary

Introduction

In the last ten years, there has been a great increase in the international consumption of tropical vegetable juices, including pumpkin, according to FAO (Food and Drug Administration. 1989). Total sugar content in the flesh was 3 times higher than that in the funicular attachments of the seeds, fibre and skin [13,14], whereas, conservation of vegetables by thermal treatment aiming to increase the life, controlling the action of enzymes and microorganism activity may affect the physical and chemical characteristics of the juice, leading to variations in the sensorial and nutritional characteristics. Alterations in this sense are inevitable but the optimization of the process would decrease the problem considerably. J Nutr Food Sci 5: 371. doi:10.4172/2155-9600.1000371 as a natural juice are capable of modifying the hydrolysis of cell wall polysaccharides with conventional thermal and exogenous enzymes pre-treatments for modification of sugar composition of pumpkin juice , improving the quality of pumpkin juice

Methods

Analytical methods

Results and Discussion

60 Water blanching

Conclusion