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The effect of slow-freezing at -20°C and liquid nitrogen freezing (LNF) at -196°C on drip, oil absorption, and carotenoid retention in frozen carrots was investigated. The loss of fluid on thawing as evaluated by centrifugation was 4 % in the slow-freezing samples, and 1 % in the LNF samples. The difference in drip between the two treatments may be attributed to the change in cell wall structre having the alow-freezing process at -20°C. Slow freezing causes damage to the structure and texture of frozen carrots due to crushing and tearing of the tissues during ice formation. When the frozen carrot slices were thawed at room temperature for one hour and then reach 3 %. Oil fried in salad oil at 160 to 170°C for 30 to 60 seconds, the oil absorption by the carrot tissue may absorption by the carrot slices varied with degree of thawing, time of frying, and the methods of freezing. Frying time influences greatly the quantity of oil absorbed by the carrot tissue. Caroten oid pigments in frozen carrots are quite stable. Freezing temperature does not affect the level of provitamin A in the frozen products. There was a slight decrease in provitamin content in the fried product due to the extraction of the carotenoid pigments by the frying oil. Because of the short time of frying at moderate temperature, the retention of the provitamin A in the product was satisfactory. The fried product has an attractive color, aroma and flavor.

A wireless solid state temperature monitoring system (Data Trace Temp, Ball Corporation, Electronic Systems Division, Westminster, CO)* was adapted and modified to monitor and optimize continuous meat cooking operations. The basic unit, a probe, is constructed from a small self-sustained microprocessor encapsulated in a stainless stell housing approximately (1 × 1 in). It is attached to a termistor available in different sizes and thicknesses. The probe's termistor tip is inserted into the center of the product. The preprogrammed probes move with the product through the process, recording temperature at preinstructed intervals, and at the end of the process transfer the stored temperature data to a microcomputer which processes the data as instructed to provide accurate time-temperature records. The cooking time of extended Salisbury steaks in a continuous multipurpose oven (MPO) was found to be reduced as much as 36%, depending on the type and level of the extender, initial moisture and fat levels, and water holding capacity of the product. Fastest cooking was achieved by the Texturized Soy Protein Concentrate (TSPC)(Central Soya) and by the 10% bread crumbs. Initial elevated fat levels accelerated the salisbury steak cooking, and initial elevated moisture content increased the cooking time. The incorporation of meat extenders improved cooking yield. Extending the product with 10% bread crumbs (BC) reduced yield loss to 6.6% of the initial weight. In comparison, all-meat products (unextended meat) could lose up to 24.6% of their initial weight. A 10% TSPC steak showed an unsignificantly slightly higher yield loss of 8.1%; however, it exhibited superior texture and the least amount of fracture damage in handling. Elevated fat levels increased the yield loss of the various products tested. A direct relatinship was found between moisture loss and cooking time which may be explained by the heat loss in the evaporating water. Energy calculations indicated that in all-meat products, of the total heat input to the product, up to 67% is used to evaporate moisture. The heat loss prolongs the cooking process, where the evaporated moisture is a major factor in the yield loss. In products extended with 10%TSPC, only 20.86% of the energy input is used to evaporate water, resulting in reduced cooking time. No such correlation was found between fat loss and reduced cooking time.

Fresh, mature kiwifruits, not suitable for the fresh market, were used to prepare frozen kiwifruit concentrate. Sucrose, 62 DE corn syrup and high-fructose Cornsweet 55 were used either alone or in various combinations on the same dry basis to prepare six sweetener types. The acidity, soluble solids, and ascorbic acid content of the fresh kiwifruit pulp and concentrates are presented. The high performance liquid chromatography method (HPLC) was used to quantitatively analyse the oligosaccharides present in the concentrates. Colour measurements made with a Hunter colour difference meter indicated that the kiwifruit concentrates differed in colour attributes, depending on the holding temperature. Objective measurements with a Brookfield viscometer indicated that the consistency of the concentrates varied with the sweetener types. The concentrate made with 62 DE corn syrup and sucrose (1:2) was thickest in consistency. Kiwifruit nectars prepared from frozen concentrates sweetened with either sucrose alone or Cornsweet 55 alone were preferred by the taste panel to the others.

The preparation of oligogalacturonic acids on a relatively large scale has been achieved by chromatography on a DEASE-Sephadex A-50 column (80 x 10 cm). The yield of oligogalacturonic acids (degree of polymerization = 1–9)recovered from the hydrolysate of polygalacturonic acid (PGA) was 54.8%. Trigalacturonic acid was obtained in highest yield when 11 of 1% PGA solution was hydrolysed by 200 mg of pectinase at 35° for 15 min. An improved thin-layer chromatographic (TLC) method was used for the detection and identification of the oligogalacturonic acids. The effects of thin-layer plates, solvent systems and spray reagents on the TLC behavior of the oligogalacturonic acids have been studied. The solvent ethyl acetate-acetic acid—water (4:2:3, v/v/v) gave the best separation on an Eastman E-13255 cellulose plate when developed twice in an ascending direction at 25°. A double spraying technique, spraying first with alkaline solution then with the chromogenic reagent, was developed with successful results. The quantitative determination of the oligogalacturonic acids by TLC is also reported.

1. 1. Among a considerable number of yeast species, representing nearly all yeast genera, only six were found which were capable of causing certain changes in pectin, when grown in its presence. These six cultures could all be identified with Saccharomyces fragilis (and a variety of this species) and its imperfect form Candida pseudotropicalis , as well as certain varieties of the latter. (See Discussion section.) These organisms cannot use pectin as a source of carbon, but require an added sugar for development. 2. 2. S. fragilis var. No. 351 was used for most of the studies reported herein. When it was grown in the presence of pectin, clarification of the liquid culture media took place with the formation of an amorphous precipitate consisting of about 1% of the pectin added. The jellying power of the pectin is destroyed, but the amount of calcium pectate and alcohol precipitate, obtainable from a clarified solution, is practically unchanged as compared to control solutions. 3. 3. The action was found to be due to an exocellular, nonadaptive, polygalacturonase-like enzyme, free of pectinesterase. The action of this yeast polygalacturonase is characteristic in that pectic acid, when used as a substrate, is only partially hydrolyzed. In contrast to fungus polygalacturonase, the enzyme cannot hydrolyze pectic acid completely to monogalacturonic acid. The velocity constant of the (initially) first-order reaction was found to be 0.196 at 22 °C. and at a pH of 3.40. The optimum pH was approximately 3.5–4.0, and the maximum rate was in the region of 55–60 °C.

The effect of commercial processing (blanching and/or roasting) on total vitamin B6 retention in processed almonds (Prunus amygdalus, Batsch) was investigated. The yeasts Saccharomyces uvarum and Kloeckera apiculata were used as comparative test organisms for the assay. Different values for vitamin B6 content were obtained from the same samples by using different test organisms. The use of K. apiculata resulted in significantly higher values for total vitamin B6 content than those obtained using S. uvarum. These differences in vitamin B6 values could be attributed to the inherent differences in the nutritional requirements of the two yeasts to vitamin B6 and to the differences in the natural responses of the two organisms towards the different forms of vitamin B6. The overall results obtained indicate that both blanching and roasting processes resulted in some loss of vitamin B6 content. Roasted almonds retained approximately 76% (with S. uvarum) and 74% (with K. apiculata) of their initial vitamin B6 content. Similarly, blanched almonds retained 88% (with S. uvarum) and 87% (with K. apiculata) of their initial vitamin B6 content. Almonds that were blanched and then roasted retained approximately 78% (with S. uvarum) and 73% (with K. apiculata) of their initial vitamin B6 content. The total vitamin B6 content of the natural unprocessed (raw) almonds was 0.83 μg/g (with S. uvarum) and 1.74 μg/g (with K. apiculata) on a dry-weight basis. These values were used as the basis for calculating the percent retention in the processed almond samples.

Various properties were studied of the exocellular polygalacturonase of the yeast Saccharomyces fragilis (strain #351). Yeast polygalacturonase (YPG) was partially purified, until the activity was 2.03 (PGu)mgTN. YPG is not accompanied by pectinesterase. The initial rate of pectic acid hydrolysis was about 158 times as fast as that of pectin (N.F.). Up to about 0.00147 PGu/ml. of pectic acid reaction mixture, the initial velocity of hydrolysis was proportional to the enzyme concentration. The extent of hydrolysis of pectinic acids of increasing methoxyl content (prepared by alkali-demethoxylation of pectin) was an inverse linear function of the methoxyl content. By addition of purified orange pectinesterase to YPG in the presence of Mg ++ , the initial rate of pectin hydrolysis approached that of pectic acid hydrolysis. The maximum extent of hydrolysis of pectic acid was found to be about 48% (based on polyuronide content). The optimum pH was found to be 4.4. YPG was found to be less contaminated with other hydrolases than fungal PG preparations, and on the basis of experience with a limited number of substrates was found to be specific for pectic acid. Of a number of enzyme inhibitors, only nitrous acid showed significant inhibitory action on YPG.

1. 1. The change in molecular weight of pectin (N.F.) due to the action of YPG has been studied. The weight-average molecular weight decreased from 56,200 to 15,100, and the number-average molecular weight dropped from 26,000 to 11,000. Good agreement was found between the extent of breakdown based on increase in reducing value and decrease in weightaverage molecular weight. 2. 2. At pH 5.0, pectic acid was found to be randomly hydrolyzed to a mixture of mono-, di-, and trigalacturonic acids. A procedure is described for the isolation of the last two acids in pure form. 3. 3. The naphthoresorcinol reagent is largely specific for monogalacturonic acid. In samples containing 50 μg., digalacturonic acid produces 7% of the color produced by monogalacturonic acid, trigalacturonic acid 3.5%, whereas tetragalacturonic acid and pectic acid give the same color as the blank. In mixtures with monogalacturonic acid, the interference appears to be somewhat less. 4. 4. During the initial very rapid rate of hydrolysis of pectic acid, in which about 25% of the glycosidic bonds are hydrolyzed, monogalacturonic acid does not appear in significant quantities as an end product. During the second slow phase in which the per cent hydrolysis increases to about 48, monogalacturonic acid formation roughly parallels the splitting of glycosidic bonds.