THE EFFECTS OF THERMAL AND NONTHERMAL PROCESSING METHODS ON APPLE CIDER QUALITY AND CONSUMER ACCEPTABILITY

Due to increased concern about the safety of fruit, vegetable and juice products, the FDA has mandated that these must undergo a 5‐log reduction in pathogens. The development of various processing methods for juice products has caused the need to determine the effects of these methods on said products. The effect of thermal pasteurization, UV irradiation and ozone treatment on apple cider quality and consumer acceptability was studied over 21 days. Thermally pasteurized samples were different in color and less preferred in all areas of consumer acceptability. UV‐irradiated samples were lower in soluble solids for the first 7 days and showed no significant difference in consumer acceptability. Ozone‐treated cider had greater sedimentation, lower sucrose content and a decrease in soluble solids by day 21. UV irradiation allows for a more cost‐effective method to produce safe apple cider with minimal quality and consumer acceptability differences.     

EFFECT OF MILK PROTEINS AND STABILIZER ON ICE MILK QUALITY

Ice milk mixes were made with and without stabilizer/emulsifier as well as with and without milk protein isolate (sodium caseinate or whey protein isolate). The mixes were evaluated for rheological, freezing, melting, and sensory properties. Adding a stabilizer/emulsifier blend to ice milk changed its physical properties more than adding milk protein isolates. The mixes with stabilizer/emulsifier exhibited increased viscosity and chewiness and decreased drainage rate, iciness, and vanilla flavor intensity. The mixes with added caseinate exhibited increased viscosity compared with those with added whey protein isolate. Overall, the quality of ice milk mix was more dependent on stabilizer/emulsifier addition than on milk protein isolate addition.     

EFFECT OF PROCESSING ON SOME CHEMICAL CONSTITUENTS OF PISTACHIO NUTS

The effect of processing on changes in fatty acids, sugars and amino acids in pistaschio nuts during blanching, drying and roasting was monitored. Blanching in hot water led to some loss in fatty acids, sugars and amino acids. Roasting further decreased the availability of the constituents. The magnitude of loss of the constituents was in the following order: blanching > roasting > drying. The composition profile of each of the constituents was analyzed. There was variation in the distribution of fatty acids among the raw and processed nuts. Unsaturated fatty acids were more susceptible to changes during processing. The combined loss of oleic and linoleic acids amounted to 22.29% of that present in the raw nuts. Fructose, glucose, sucrose and raffinose were shown to be present in the nuts. The loss of sucrose was higher than the monosaccharides during processing. Glutamic acid, leucine, proline 56.50% of the amino acids present, and blanching, drying and roasting successively caused losses in the availability of these amino acids. The effect of processing on nutritional values has been a subject of concern to consumers and food processors. The present investigation reveals that the loss in various components in the nuts deserves more attention.     

EFFECT OF PROCESSING VARIABLES ON MICROBIAL QUALITY AND SHELF-LIFE OF BLUE CRAB (CALLINECTES SAPIDUS) MEAT

The effects of cooking time, cooking method, season, and storage condition on the microbiological quality, sensory characteristics, and shelf-life of crabmeat were determined under commercial processing conditions. Microbial flora content of the meat was inversely proportional (p 0.05) to the cooking time in both total aerobic and anaerobic plate counts after 6 and 9 days at 2.2C during summer. Boiled cooked crabmeat showed higher microbial count (1–2 log cycle) and shorter shelf-lives than 10 and 12 min retort cooked meat. During summer, the shelf-life of the meat as determined by a sensory evaluation, was: 15.5 days at 0.0C; 12.5 days at 2.2C; and 8.5 days at 5.6C.     

THE INFLUENCE OF THE REFRIGERATED FARM BULK MILK TANK ON THE QUALITY OF THE MILK AT THE PROCESSING DAIRY

A brief review is given of the bacteriology of bulk milk collection, with particular reference to the total bacterial content of the raw milk at different stages of collection. This is followed by a consideration of appropriate reference, routine and simplified tests and standards for the bacteriological quality control of bulk collected milk.
It is recommended that the total colony count, thermoduric count and coliaerogenes count, all at 27°C, should always be used for investigational, survey and advisory work. As these tests are too laborious, slow and expensive for the routine fortnightly grading of farm bulk tank milk supplies at creamery laboratories, a modified resazurin test at 30°C is prescribed for this purpose.     

THE EFFECT OF ANTIOXIDANTS ON THE KEEPING QUALITY OF SPRAY-DRIED WHOLE MILK POWDER

Spray-dried whole milk powders containing either 0.01 per cent ascorbyl palmitate or this compound plus 0.01 per cent citric acid were prepared and their keeping quality under accelerated storage conditions at 37°C compared with control powders and powders containing dodecyl gallate. Ascorbyl palmitate alone afforded little protection against oxidative deterioration but together with citric acid considerably improved keeping quality. Although the addition of several antioxidants to edible oils and fats and butter intended for manufacture is permitted, their addition to milk powder is forbidden (Regulations, 1966). There are several reasons for this discrimination, the chief of which lies in the phenolic nature of the most effective antioxidants in spray-dried whole milk powder (Findlay, Smith & Lea, 1945). More recently ascorbyl palmitate has been used to delay the onset of oxidation in butter (Koops, 1964) and milk fat (Englelhardt & de Man, 1963). It seemed appropriate therefore, despite the different chemical composition and physical condition of the fat in butter and in milk powder, to examine its effectiveness in the latter product. In the quantity employed (0–01 per cent), ascorbyl palmitate would not present a risk to health, and its usefulness could probably be enhanced by the addition of a simple synergist such as citric acid, known to be effective with dodecyl gallate in lard (Lea, 1958).     

EFFECT OF CARRAGEENAN ON PROCESSING AND QUALITY CHARACTERISTICS OF LOW-FAT FRANKFURTERS

Three types of carrageenan (K, I, K+I) × 4 levels (0, 0.25, 0.5 and 1.0%) were evaluated with a complete factorial design to characterize the effect of carrageenans on processing and quality characteristics of low-fat frankfurters (9% fat, 13% protein). l-Carrageenan at 0.5–1.0% level appeared to be more beneficial for the production of low-fat frankfurters. It reduced (P<0.05) the hardness of the skin and contributed to a softer (P<0.05) product and higher overall acceptability. Low-fat frankfurters (9% fat) manufactured with I-carrageenan (IC) or in combination with finely ground toasted bread (TB), isolated soy protein (ISP) and pork skin (PSK), were compared to high-fat (27% fat, 11% protein) and to low-fat (9% fat, 13% protein) control frankfurters prepared with 3.5% potato starch (PS), as well as with commercial frankfurters (25% fat, 11.6% protein, 4.5% starch). Frankfurters with IC had higher (P<0.05) moisture, softer (P<0.05) skin and the highest (P<0.05) separation of gelatin. However, textural properties and overall acceptability were similar (P>0.05) to commercial and high-fat control frankfurters. Addition of TB had no significant effect. Use of ISP and PSK improved (P<0.05) the water-binding capacity but negatively affected the overall acceptability of frankfurters.     

耐热性脂肪酶及其对UHT乳品质的影响

UHT(超高温)乳饮用方便、营养丰富、备受消费者欢迎,近年来在我国的乳品消费结构中增长迅速,但是UHT乳在整个贮存过程中常因其中残留的脂肪酶、磷脂酶等因素而导致脂肪上浮、脂肪分解等现象,使产品的风味、品质变差,主要从耐热性脂肪酶对UHT乳品质的影响出发,综述了国内外对牛乳中主要耐热脂肪酶的研究现状,并提出今后深入研究应关注的方向.     

EFFECT OF TEMPERATURE AND WATER CONCENTRATION DURING PROCESSING ON FOOD QUALITY

Water content and temperature during food processing have a pronounced influence on the rates of those changes in food properties which are the object of the process such as reduction in water content or sterilization. However, they also strongly influence adverse side effects such as browning, loss of nutrients or shrinking. When the effects of temperature and water concentration on the process rates of the desired and adverse processes are known, the processes can be optimized. An example of the optimization procedure is given for the spray drying of heat-labile aroma containing liquid foods. Both temperature and moisture content of the droplets change with time in spray-drying. In a second example a new and simple calculation method is introduced for the optimization of quality retention in the sterilization of packed foods.