Effects of Four Cooking Pressures on Locally Grown Broccoli: Cooking Time, Palatability, Ascorbic Acid, Thiamine, and Riboflavin

Abstract

The purpose of this study was to determine the effects of increased temperature, with increased pressure, on total cooking time, palatability, ascorbic acid, thiamine, and riboflavin retention in locally-grown broccoli. It is known that in pure solutions ascorbic acid, thiamine, and riboflavin are affected in the presence of heat. The cooking methods used besides boiling at atmospheric pressure were 5, 10, and 15 p.s.i.g.Brinkman, Halliday, Hinman, and Hamner (2) reported that fresh broccoli was definitely inferior in palatability when cooked in the pressure saucepan.The ascorbic acid content of broccoli has been reported in the literature to range from 68 mg. per 100 g. by McHenry and Graham (11) to 128 rt 6 by VanDuyne, Bruchart, Chase, and Simpson (16) and 128 A 7 by Collings (5). The range of retention of ascorbic acid during cooking of broccoli has been reported from 38% by Burrell and Elbright ( 3 ) to 69 +-3 to 77 c 6% by Collings ( 5 ) .The thiamine content of broccoli has been reported in the literature from as low as 0.08 mg. per 100 g. by Morgan, MacKinney, and Gailleau ( 1 2 ) to 0.202 by Banton ( 1 ) . Retentions in drained cooked broccoli ranged from 87% to complete retention as reported by Collings ( 5 ) depending upon the proportion of water used a t 0, 5, o r 15 lb. pressure. Oser, Melnick, and Oser (15) reported 95% retention in broccoli cooked by boiling.The range of riboflavin content of broccoli has been reported from 0.176 mg. per 100 g. by Hodson (9) to 0.320 by Oser, et al. ( 1 5 ) . Reported retentions in drained cooked broccoli range from 83% by Oser, et al. (15), and from 83% to complete retention by Collings ( 5 ) depending upon the method of cooking. Collings also reported some increases of riboflavin during cooking. EXPERIMENTAL PROCEDURESThe broccoli was of Calabrese variety and wag grown at Geneva, New York. Onehalf ton of 4-8-12 fertilizer was used per acre. The broccoli was dusted three times during the season with a rotonal duster. It was delivered to the laboratory the afternoon it was cut, and was placed in the hydrator of a refrigerator. It was cooked the following morning.Preliminary preparation. The broccoli was trimmed and washed i n running cold water. It was drained in a shallow pan lined with cheese cloth. The stalks were cut into four-inch lengths, and the larger stalks were split lengthwise.Cooking. For cooking a t each of the four pressures, a four-quart alumnium pressure saucepan having a diameter of eight inches and a depth of five inches was used. I n the studies employing atmospheric pressure the vent in the cover was left open. I n order to determine when the air was exhausted from the pan, and also to check the 409