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SUMMARY– A problem arises if juice extracted from raw carrots is heated to about 180° before or during conventional canning practices. An unsightly, unappetizing coagulum forms and the color of the juice precipitates with the coagulum. The coagulum is not as evident if the carrots are heated 5 min in water prior to juice extraction, but the juice loses some of its bright‐orange color. The canned juice extracted from carrots heated 5 min in a .05 N acetic acid solution does not coagulate and the amount of juice which can be extracted from the carrots is 3.3% greater than that from carrots heated 5 min in water. The centrifuged juice from acid‐treated carrots had a brighter orange color than juice from the water‐treated carrots. The color notation was Rd, 23.7, a, 30.4 and b, 34.8 for juice from acid‐treated carrots compared with a notation of Rd, 19.2, a, 24.4 and b, 31.4 for the juice from water‐treated carrots. The canned juice extracted from raw carrots had less pectic substances and starch and about the same amount of protein as the canned juice from the carrots heated in water or .05 N acetic acid, but the canned juice from raw carrots coagulated. The juice from carrots heated in acid does not form a coagulum and maintains its orange color, probably because of the action of the heat and acid on the protoplasmic liquid of the cell before or immediately after the cell is ruptured.

Jalapeno peppers were canned and treated with calcium chloride, calcium hydroxide, and calcium lactate. Concentrations of 0.2, 0.3, and 0.4% of calcium were used. After 3 months of storage time, the peppers were evaluated for texture, quality, and nutritional composition. Calcium hydroxide was an inadequate firming compound in this experiment because of its neutralizing effect on the acid content and the precipitation found in the can after storage. Calcium chloride at a concentration of 0.2% was found to be the most desirable firming compound because under the test conditions it did not impart a bitter taste and because its solubility properties are better than those of calcium lactate. Higher concentrations failed to significantly increase the firmness of peppers. The treatments produced no adverse effects on the flavor or the vitamin and mineral content, with the exception of calcium, in canned jalapeno peppers.

Corn and flour tortillas were sampled at 2-wk intervals for 6 wk from five tortilla factories and the nutritional composition determined. Corn tortillas were found to be slightly lower in protein, thiamin, riboflavin and niacin when compared to white enriched bread. A lowering of the pH of the corn masa to 7.3 or lower improved the retention of these vitamins. Flour tortillas were found to be comparable in nutrition to white enriched bread when enriched wheat flour was used in the manufacture of tortillas. A wide variation was found to exist in the nutrient composition of both corn and flour tortillas manufactured by the different factories. This variation is attributed to different formulation procedures at the tortilla factories.

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