Spinach blanching

Figure 2. Chlorophyll and chlorophyll derivatives of spinach a) unblanched, b) blanched 3 min at 160°F (71°C) c) blanched 3 min at 190°F (88°C) C = chlorophyll, CD = chlorophylllde,...

Clydesdale and Francis (.8) attempted to Increase the amount of chlorophylllde produced in spinach during blanching in order to study its role in color retention. Blanching for 10 minutes at 155°F (68.3°C) and at a pH of 8.5 resulted in a 60% conversion of chlorophyll to chlorophylllde a. while inhibiting the formation of pheophorbide. However, the amount of chlorophylllde formed represented only 29.7% of the total pigments and decreased to 8.2% after processing at 240°F (116°C) (F0 = 4.9). None remained after 2 weeks of storage at 20°C. Spinach processed after enzyme... 

Green peas, green beans, Brussels sprouts and spinach are the most consumed frozen green vegetables. These vegetables are blanched prior to freezing to... 

In addition to water and steam blanching, use of micro-wave energy was demonstrated to be a convenient and effective method of blanching [7] and superior in retention of ascorbic acid. The texture of rehydrated, microwave-blanched freeze-dried spinach was firm, chewy, and highly acceptable. 

Water activity has been shown to have a definite influence on the rate of degradation of chlorophyll in freeze-dried, blanched spinach puree [73]. At 37°C and an higher than 0.32, the most important mechanism of chlorophyll degradation was conversion to pheophytin. At lower than 0.32, the rate of pheophytin formation in spinach was low. The rate of chlorophyll-a transformation was 2.5 times faster than chlorophyll-. The study of the degradation of chlorophyll as a function of a . pH, and temperature in a spinach system... 

N.M. Quentzer and E.E. Bums, Effect of microwave steam and water blanching in ffeeze-dried spinach, J. Food Sci., 46(2) 410 (1981). 

In view of the limited data on these commodities we deemed it worthwhile to make a few color measurements on extreme cases. Blanched frozen peas and spinach were therefore thawed, portions blended, then centrifuged to remove air bubbles. Other portions were heated in the presence of dilute oxaUc acid, and treated as before. Canned peas and... 

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