Bosscher D, Lu Z, Van Cauwenbergh R, Van Caillie-Bertrand M, Robberecht H, Deelstra H
University of Antwerp (UIA), Department of Pharmaceutical Sciences, Laboratory of Food Sciences, Universiteitsplein 1, B-2610 Antwerp (Wilrijk), Belgium.
Int J Food Sci Nutr. 2001 Mar;52(2):173-82. doi: 10.1080/713671769.
A method for in vitro determination of available calcium, iron and zinc content from infant food after digestion was evaluated. This method introduced an intraluminal digestive phase, adapted to the gastrointestinal conditions of infants younger than 6 months of age, prior to continuous flow dialysis of the resultant gastric digest. Precautions handling the method were discussed and enzymatic parameters were defined. Ruggedness of the method was determined from the availability of calcium, iron and zinc at different gastrointestinal conditions. Availability of all three elements was higher at gastric pH of 2 (20.0 +/- 1.1% for calcium, 4.06 +/- 0.66% for iron and 17.5 +/- 1.3% for zinc), than from the normal procedure (pH 4) (15.6 +/- 1.2% for calcium, 1.18 +/- 0.26% for iron and 8.2 +/- 0.9% for zinc). At pH 5, however, calcium availability appeared to be lower (11.7 +/- 1.0%) (P < 0.05). The intestinal pH also had a major influence on the availability. At low intestinal pH (5.5), availability was 40.5 +/- 2.3% for calcium, 3.01 +/- 0.58% for iron and 26.8 +/- 1.8% for zinc, which was higher compared with the normal procedure (P < 0.05). Moreover, other factors, such as digestion time, mixing and filtration pressure, also affected the availability. Recovery tests yielded mean values of 94 +/- 3% for calcium, 109 +/- 9% for iron and 106 +/- 4% for zinc. Mean intra- and inter-batch precision of the availability procedure was 4.1 CV% and 6.6 CV% for calcium, 14.5 CV% and 19.2 CV% for iron, and 4.0 CV% and 13.6 CV% for zinc. The method provides adequate accuracy, acceptable precision and good recovery. It offers the advantage of being simple, rapid and inexpensive, since it takes only 1 day to run the whole availability procedure (including four replicates per sample), and the low costs of the dialysis equipment. It can therefore be considered as suitable for predicting the availability of essential elements from foods used during the first months of infancy.
评估了一种体外测定婴儿食品消化后可利用钙、铁和锌含量的方法。该方法在对所得胃消化物进行连续流动透析之前，引入了一个管腔内消化阶段，以适应6个月以下婴儿的胃肠道状况。讨论了该方法的操作注意事项并定义了酶参数。根据不同胃肠道条件下钙、铁和锌的可利用性确定了该方法的耐用性。在胃pH值为2时，所有三种元素的可利用性均高于正常程序（pH值4）（钙为20.0±1.1%，铁为4.06±0.66%，锌为17.5±1.3%），正常程序下钙为15.6±1.2%，铁为1.18±0.26%，锌为8.2±0.9%。然而，在pH值为5时，钙的可利用性似乎较低（11.7±1.0%）（P<0.05）。肠道pH值对可利用性也有重大影响。在低肠道pH值（5.5）时，钙的可利用性为40.5±2.3%，铁为3.01±0.58%，锌为26.8±1.8%，与正常程序相比更高（P<0.05）。此外，其他因素，如消化时间、混合和过滤压力，也会影响可利用性。回收率测试得出钙的平均值为94±3%，铁为109±9%，锌为106±4%。可利用性程序的批内和批间平均精密度，钙分别为4.1 CV%和6.6 CV%，铁分别为14.5 CV%和19.2 CV%，锌分别为4.0 CV%和13.6 CV%。该方法具有足够的准确性、可接受的精密度和良好的回收率。它具有简单、快速和廉价的优点，因为整个可利用性程序只需1天（包括每个样品四个重复），且透析设备成本低。因此，它可被认为适用于预测婴儿出生后最初几个月所食用食物中必需元素的可利用性。
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