No abstract

Activation of the natural milk lactoperoxidase system (LPS) and a simple means for evaporative cooling (EC) were tested on three small dairy farms in a rural area of Kenya. Lactoperoxidase activation was accomplished by adding pre-weighed quantities of sodium carbonate peroxyhydrate (0.04 g/l) and sodium thiocyanate (0.03 g/1) to 51 quantities of freshly collected bovine milk. Containers were covered with two layers of jute fabric which was thoroughly saturated with water to enhance natural cooling by evaporation. The experiment included four storage treatments: (1) untreated control, (2) LPS, (3) LPS/EC, and (4) refrigerated control. The storage time at outdoor ambient temperatures ranging from 14 to 20°C was 20 to 22 h. Milk quality was estimated by standard plate counts, coliform counts, the 10-min Resazurin test, and total acidity. The experiment was replicated six times. Refrigerated storage resulted in excellent quality milk, followed by LPS/EC treatment. The latter was adequate to produce milk considered to be acceptable for processing after 20 to 22 h in 13 out of 18 cases. LPS treatment alone was not adequate. Sensory analysis of LPS/EC milk that was subsequently pasteurized revealed acceptable flavor. The LPS/EC treatment has potential for reducing milk spoilage and increasing the supply of marketable milk in countries which lack facilities for refrigerated cooling.

High protein yoghurt was made from whole milk, fortified with egg white (30% v/v) and skim milk powder at 12% (w/v). Different yoghurt mixes, with albumin content of 15%, 30% and 45% (v/v), were prepared. The control was made from whole milk, fortified with skim milk powder at 12% (w/v). The blended premixes were pasteurized at 74ºC for 4 seconds, cooled and then inoculated with 3% (w/v) Direct Vat Set yoghurt starter culture at 45ºC. After fermentation for 3 hours in a water bath maintained at 46+-1C, product was cooled to 5ºC and then stored for 24 hours. The effect of the fortification on physico-chemical and sensory properties was investigated. Protein content increased to 8.50% at 45% egg white utilization. Susceptibility to wheying was reduced in egg-white fortified samples, without signicant difference in sensory attributes of the test samples compared to the control. Sensory analysis showed that yoghurt fortified with 45% egg white was organoleptically acceptable. The yoghurt was rated as having better sensory appeal as compared to the control.

High protein yoghurt was made from whole milk, fortified with egg white (30% v/v) and skim milk powder at 12% (w/v). Different yoghurt mixes, with albumin content of 15%, 30% and 45% (v/v), were prepared. The control was made from whole milk, fortified with skim milk powder at 12% (w/v). The blended premixes were pasteurized at 74 • C for 4 seconds, cooled and then inoculated with 3% (w/v) Direct Vat Set yoghurt starter culture at 45 • C. After fermentation for 3 hours in a water bath maintained at 46±1 • C, product was cooled to 5 • C and then stored for 24 hours. The effect of the fortification on physico-chemical and sensory properties was investigated. Protein content increased to 8.50% at 45% egg white utilization. Susceptibility to wheying was reduced in egg-white fortified samples, without significant difference in sensory attributes of the test samples compared to the control. Sensory analysis showed that yoghurt fortified with 45% egg white was organoleptically acceptable. The yoghurt was rated as having better sensory appeal as compared to the control.