Effect of fat incorporation on properties of sterile concentrates prepared by ultrafiltration of skimmed milk

The preparation and properties of sterile concentrates, based on milk concentrated by ultrafiltration with added carbohydrate, are discussed. Methods are given for optimization of initial heat stability and shelf life. The new products are sweet but suffer from no apparent technical obstructions to their commercial exploitation.     

Effect of starches on the heat stability of milk

Starches from different botanical sources have been added (0.5–1.5% w/w) to skim milk and pregelatinized by heating at 70°C for 30 min. the heat coagulation time (HCT) of the milk-starch mixtures was then evaluated at 140°C. the addition of native starches to milk had a destabilizing effect. Increasing the concentration of added starch caused a decrease in HCT's. the reduction in the heat stability of milk proteins was not related to the amylose/amylopectin composition or to the granular structure of the starches. Modification of the molecular properties of the starch components by acid hydrolysis or cross-linking resulted in an enhancement of the heat stability of the mixtures.     

Sensory properties of kishk: comparison of products containing bovine and caprine milk

There is growing consumer interest in fermented milk and in products containing fermented milk because of their nutritional value and healthy image. Kishk, a traditional product of Middle Eastern origin, has been examined with a view to developing its potential for a wider market. Kishk is traditionally made from a dough, containing yogurt, parboiled cracked wheat and salt, which is sun dried then ground to a flour. The flour may be consumed in a variety of ways, but one popular use is in the preparation of a hot, porridge like gruel. This paper describes the sensory profiles of gruel made from 15 samples of kishk and compares them with those of two traditional Scottish oatmeal porridges. Substantial differences were noted between kishk and the oat based products. In addition, there was evidence that the origin of the fermented milk component of the kishk was important. Kishk made from fermented caprine milk was clearly distinguished from that made with yogurt of bovine origin. It was noted that many of the kishk samples were rated highly for bitterness and for cardboard character. Such attributes are believed to be disliked by consumers in the United Kingdom .     

SIMULATION of CANOLA and BARLEY DRYING IN A DEEP BED

A mathematical model for a radial, continuous-crossflow dryer was modified and used to simulate the drying process in a fixed bed dryer. the predictions of the adapted model were compared with experimental test results for canola drying at the following drying conditions: airflow rates of 0.4 and 0.6 kg/(m²s), inlet air humidity 0.098 and 0.0114 kg/kg of dry air, initial grain moisture content 0.221 and 0.251 kg/kg dry basis. In both tests the inlet drying air temperature was kept at an average of 67.5°C. At the end of canola drying, the mean drying air temperature predicted by our model was within 1°C of the measured temperature and the mean predicted moisture content was within 0.5% of the measured moisture content, dry basis. Also, our model was verified against experimental results for barley published by other authors and against predictions from a published model for barley. the predictions from our model were in good agreement with the published experimental and predicted data. Simulations results for canola and barley drying in the same thickness of a deep bed were compared. Simulations were conducted to investigate the effects of canola properties such as bulk density and dryinig conditions of air such as airflow rate and air humidity on drying in deep beds of canola.     

Natural variation in heat stability of concentrated milk before and after homogenization

An examination has been made of the seasonal variations in the heat stability of skimmed milk, concentrated (22.5 per cent total solids) skimmed milk, and concentrated (31 per cent total solids) whole milk. Marked seasonal differences were found to exist in the effects of homogenization on the heat stability of subsequently concentrated milk. 'Summer' milks were found to be much more stable than 'winter' milks after homogenization and to be more readily stabilized by added sodium phosphates and citrate. Milk serum rather than milk fat was shown to be the major determinant in the heat stability of concentrated homogenized milk, and all such milks were found to be very sensitive to small changes in their level of soluble calcium.