THE USE OF CONTROLLED LEVELS OF ACTIDIONE FOR BREWING AND NON-BREWING YEAST STRAIN DIFFERENTIATION

The variability of results using actidione media for the identification of beer spoilage bacteria has been shown to be due to the heat sensitivity of this reagent. Critical evaluation shows that with a particular brewery yeast, media containing 0·06 p.p.m. allow the growth of a single brewing strain but inhibit others. This permits the rapid classification of yeast strains in this pitching yeast. In a further brewery, media containing 0·16 p.p.m. differentiate brewing yeast strains from beer spoilage yeasts and this permits the quantitative assessment of these for process control at all stages of brewing. In a particular instance where a culture yeast strain is not inhibited at 0·16 p.p.m. but is p-aminobenzoic acid dependent, a differential medium incorporating this low level of actidione and omitting the vitamin allows the identification of beer spoilage yeasts in process control. These results illustrate the potential of this approach for microbiological control in specific brewery problems.     

缓释微胶囊及其在芳香保健纺织品上的应用

介绍了用于保健纺织品的香精微囊化的几种方法及用于织物整理的几种途径。利用界面聚合法、原位聚合法、复凝聚法或β－环湖精包结法等微胶囊技术制成微胶囊香精，然后通过喷雾、加入印花浆料中或采用浸轧整理液中制成芳香保健纺织品，并利用香囊缓释香味，达到治疗目的，从而开始纺织品的新市场。     

A METHOD FOR CONTROLLED OXYGENATION OF WORTS*

An improved method of oxygenation is described. This permits the introduction of precise amounts of oxygen into worts, without the creation of foam.     

USE OF THE PENETROMETER FOR DEFORMATION TESTING OF FOODS

The cone of a penetrometer is replaced by a flat, light-weight plastic horizontal disc which is allowed to compress an article of food for 5 set, after which a reading is taken from the dial of the instrument. Next a weight is placed on the upper end of the vertical shaft that carries the disc and the food is compressed again for 5 set, after which a second reading is taken from the dial. The difference between the two dial readings gives the deformation to the nearest 0.1 mm. Examples of its use on tomatoes and marshmallows are given. The test works well on foods that are deform able, but is not recommended for rigid foods because of lack of precision.     

A COMPUTER CONTROLLED MICROMALTER FOR ASSESSMENT OF THE MALTING POTENTIAL OF BARLEY CROSSBREDS

An automatic, computer-controlled micromalter with several advantages over current designs has been constructed. All operations are carried out in the one cabinet, and it is not necessary to intervene at any point during the malting process. The sample containers were constructed so that mechanical deculming of groups of ten large or fifteen small samples could be carried out in ten minutes. Initially, the capacity of the micro malter was 40 × 100 gm or 70 × 60 gm samples. These capacities were doubled by the use of longditudinal dividers slid into each canister, making the apparatus suitable for screening of samples submitted from the early generations of a breeding programme. The results obtained by malting 36 large and 60 small samples of the same variety; six replicates of six varieties; and subsamples of a bulk of a single variety in 37 subsequent runs all indicated that the instrument provided satisfactory separation and ranking between samples of differing malting qualities and grouped samples of similar malting qualities together.     

CONTROLLED HEAT PROCESSING OF JEWEL SWEET POTATOES FOR PUREE PRODUCTION1

‘Jewel’ sweet-potato slices 0.5 cm thick were precooked at 100, 125 and 150C for varying periods of time, finish-cooked for 15 min at 150C, and pureed. Selected chemical and physical properties of the purees were compared to a puree prepared from conventionally baked sweet potatoes (1.25 h at 195C). Purees from the controlled heat process were also compared to the baked puree by a sensory panel. Of all the treatments, puree from the 100C, 6-min precook treatment was the most silimar to puree from baked sweet potatoes with respect to chemical and physical characteristics. The sensory panel found the two purees to be different, but were equally divided when asked to express a preference. Subsequent analysis showed that the starch of the baked control had been more completely hydrolyzed than the starch of the other treatments. This was reflected by higher maltose, lower starch content and by decreased starch molecular size and viscosity of the control compared with the other treatments.     

USE OF FLEXIBLE POLYMER MATERIAL FOR PACKAGING FRESH PEACHES

Fresh peaches (Prunus persica) were overwrapped in trays with 1 of 3 formulations of flexible polyvinyl chloride (PVC) film that differed in gas transmission rate or they were held in nonwrapped trays (controls). The CO₂ transmission rate at 0°C for PVC type III film was 280 mL/m^2. h (1 atmos); that of type II was 4 times greater and that of type I, about 5 times greater. The peaches were stored either 14 days at 0° or 7.5°C, or 7 days each at 0° and 7.5°C plus 2 days at 20°C to simulate retail display. The mean CO₂ levels were 10, 7.2 and 4.7% in packages that were wrapped with PVC III film and held at 7.5°, 0°/7.5° and 0°C, respectively. CO₂ in packages wrapped with PVC I or II was below 3% at each storage temperature. O₂ concentration remained about 4% in all packages. Weight loss was less and fruit was firmer among those packaged in PVC III than among nonwrapped controls at each of the 3 storage temperatures. Storage temperature had no effect on weight loss or of fruit held in PVC III film. External appearance of fruit packaged with the 3 types of film was significantly better than that of the controls. Internal appearance of the peaches was unaffected by any of the treatments. A microatmosphere favorable for fresh peaches can be maintained within packages overwrapped with polymer films that are selectively permeable to respiratory gases.     

USE OF THE CONE PENETROMETER FOR TESTING THE FIRMNESS OF BUTTER

Analysis was made of cone penetration test parameters for butters of a wide range of firmness. The relationship:
accounted for 96.9% of the variation in the observations. This relationship, which has the dimensions of stress, differs from the previously proposed rheological models. An index, based on this relationship, was found to account for approximately 91% of the variation in the sensorially perceived spreadability of the butters.