中英文翻译
(文档含英文原文和中文翻译)
附件1：翻译译文
热处理对豆奶（豆腥味）过氧化
脂质含量的影响
豆腥味是导致豆奶风味不理想的重要因素，为了以最大限度的降低豆奶的豆腥味，我们研究了热处理对过氧化脂质的影响，是影响豆腥味的一个重要因素。我们还以豆奶为原料并在制作过程中使用加热工序制备了各种甜点，从而通过感官实验来评价加热对其的影响。经过浸泡和在75℃热处理的肿涨的大豆在相对湿度80-90％处理十分钟的过氧化脂质的含量比大豆中缺乏脂氧合酶和14％或更少的热处理的大豆制备出的豆奶的过氧化脂质含量要大大降低。此外，设计热烫浸泡和肿胀的大豆在沸水中处理了30秒的豆奶的过氧化脂质含量可以与缺失脂肪氧合酶的大豆制作出的豆奶过氧化脂质含量相媲美。蛋奶布丁，巴伐利亚奶油以及经过热处理的大豆制作出的豆腐其中的豆腥味都得到了显著的改善。
关键词：大豆 豆奶 过氧化脂质 豆腥味
大豆长期以来都是作为高营养食品代名词在日本人的饮食文化中具有具足轻重的作用。最近的研究表明，大豆蛋白具有降低胆固醇的作用（爱德森等人，1995），大豆皂苷具有抗癌活性（肯尼迪，1995), 以及大豆异黄酮对乳腺癌和前列腺癌具有一定的抑制作用（彼得森&贝尔内斯,1991; 彼得森G&贝尔内斯S ，1993），以及对于骨质疏松症（土田等人，1999）具有一定的预防作用。根据以上情况可知，由大豆制成的加工食品的价值就是作为人体异黄酮的来源。大豆被用于很多的食品中，包括豆腐，纳豆，味精，酱油，豆浆。豆奶作为一种可利用的饮料，可以广泛应用于果冻，蛋奶布丁等甜品的制作原料。然而，脂肪氧合酶产生的独特的豆腥味对消费者的喜好产生了重大的影响。因此尽可能的减少豆腥味是能够使豆浆脱颖而出并广泛推广的关键性的挑战。
有几种用于激活脂肪氧合酶的方法已经被提出：温水处理研磨的方法（越后等，1991），其中，大豆在70℃热水中浸泡，然后用95℃的热水进行匀浆; 热烫（赛斯&纳特，1988）的方法，用99.3℃的热水进行处理，以及微波加热的方法（王&托莱多，1987）。然而，所有的这些方法都存在加热引起的不溶性蛋白质以及蛋白质提取率的下降（爱德威亚等，1987）的问题。欧姆拉和客市（1990）提出的把去皮黄
豆在热水中70℃5分钟使黄豆加热浸泡发胀。然而，由于在剥离的过程中与下胚轴的分离有关（恩多等人，2003），所以这个过程不适合于原料中含有高异黄酮的豆奶的制备。进行本次研究的目的是以最大限度的减少豆腥味为目标，这是影响豆浆以及豆浆相关的饮料味道的重要方面。我们研究了加热对有助于豆腥味产生的过氧化脂质含量的影响，我们准备自制甜品用这种方法进行处理从而探究其对豆制品风味的影响。
材料和方法
对以下大豆品种进行测试生长，筛选，并在福岛县农业试验站风干的大豆品种：东北126（高异黄酮大豆，恩多等人，2003b ），东北135（脂氧合酶缺失大豆，此后，固氮酶缺失大豆），东北139（低过敏源大豆品系，此后，低过敏原大豆），黑豆，青豆（青大豆）和市售大豆（枥木县产，核苷酸酶缺乏大豆）。
大豆热处理和豆奶制样被用作实验原料。
对照组：大豆在20℃水中浸泡16小时，以及添加水（6:1，水的重量:大豆的重量）然后进行热挤压的方法处理（恩多等人，2003，下同）。
试验一：大豆在75℃条件下进行空气干燥10分钟（DK-600T 培养箱，日立公司）用水漂洗，然后通过相同的方法制备豆浆如对照组所述。
实验二：大豆在相对湿度80-90%，温度75℃（MTH-4400恒定温度和湿度室中，三洋）蒸制10分钟之后并用水冲洗。然后通过相同的方法制备豆浆如对照组所述。 实验三：大豆需在20℃水中浸泡膨胀16小时，然后于75℃相对湿度80-90%条件下蒸制10分钟之后用水冲洗，与另外的水（6:1,水含量:大豆含量）通过热挤压法制备豆奶。
实验四：大都在75℃的热水中加热处理60分钟并用水冲洗，然后，与另外的水（6:1，水的重量:大豆的重量）用热挤压的方法制备豆奶。
实验五：大豆在20℃水中浸泡肿胀16小时，并在75℃热水（10:1，水的重量:大豆的重量）中烫2分钟并用水冲洗，然后在添加水（6:1，水的重量:大豆的重量）用热挤压的方法制备豆奶。
实验六：豆奶的制备与对照组的描述运用的是相同的方法，而其中不同的是大豆用95℃的热水进行匀浆。
多种品种的大豆被用于该实验，已经被20℃的水浸泡肿胀16小时的大豆在沸水中烫10-40秒，再准备以6倍体积的水加入用热挤压的方法制备豆奶。
测定过氧化脂质的含量为将0.5克32目或者更细的大豆粉末在一个紧凑的铣床（AS One 公司，奇迹搅拌机WB-1), 豆奶或者每豆奶甜品中加入十毫升蒸馏水，并将该混合物用兵冷却均化。将匀浆液静置60分钟到4之后，运用DETBA （1,3 - 二乙基-2 - 硫代巴比妥酸）方法（Suda 等人，1994）对过氧化脂质的含量进行测定。
对利用东北大豆126制成的豆浆甜品进行制备和感官评价，对豆腥味进行的一个感官评价。大豆在20℃的水中浸泡膨胀16小时后在沸水中烫（100℃）30秒，然后添加6倍体积的水并用热挤压的方法制备豆奶。甜品使用标准配方进行制备的，只是用豆奶来替换牛奶。布丁用布丁混合物（日清食品），巴伐利亚奶油采用巴伐利亚奶油混合物（日清食品），豆腐用豆腐混合物。
感官评价是采用五点量表（1：强;2:中等强度;3弱；4：几乎没有；5：完全没有）来区分豆浆的豆腥味（古河，1994）。小组成员包括来自会津若松技术支持中心（25岁到56岁；12男和3女）的15名工作人员。感官评价重复两次，测定结果为平均值。使用双因素方差分析对样本之间的差异进行了测试。蛋白质和豆浆中固体物质的提取率根据先前描述的方法（恩多等人，2003年）进行测定。
结果与讨论
正常的大豆（黄豆与脂氧合酶的活性）的过氧化脂质含量介于63.5到83.6纳摩尔，取76.2纳摩尔的平均值。大豆品种最低含量的是Shinanokuro 和最高含量的是Suzuyutaka 。对于脂氧合酶缺乏的品种为东北135和lchihime ，其过氧化脂质含量的差异很小为23.6纳摩尔和29.8纳摩尔。这些品种的平均含量为26.7纳摩尔，在正常的大豆中测的含量约35%。
作为未加工的大豆，其豆浆过氧化脂质含量的差异表现出一个类似的趋势。豆奶生产中的过氧化脂质含量从大豆的正常范围14.4到21.3纳摩尔，取平均值18.4纳摩尔。大豆生产中平均过氧化脂质含量来自脂氧合酶缺乏大豆为4.7纳摩尔，大约是正常大豆水平的26%。这些在以往的研究中获得的结论几乎是相同的（古田等人，1996）。
正己醛的含量是豆浆豆腥味的主要成分这一观点已经被报道，它的含量与过氧化脂质的含量成正比（古田等人，1996），并且所有脂氧合酶缺乏大豆所制备的豆浆产生的豆腥味小于正常大豆制备的豆浆（托雷斯-佩尼亚兰达等人，1998）。鉴于这些结果，可以得出结论最小的豆腥味的豆奶可以以过氧化脂质含量约5纳摩尔/克来制备。
I. 过氧化脂质的含量
对照组的豆浆过氧化脂质的含量为没克21.3纳摩尔。根据处理方法的不同热处理大豆过氧化脂质含量明显降低。制备的豆奶中具有最低过氧化脂质含量分别为蒸制10分钟，在75℃80-90的相对湿度处理加上浸泡和在水中膨胀的大豆（实验三，2.8纳摩尔），和在加热的热水中处理两分钟，在75℃浸泡和在水中溶胀的大豆（实验五，3.3纳摩尔）。在这两组中过氧化脂质的含量明显低于脂氧合酶缺乏的大豆制备的豆奶。下一组最低过氧化脂质含量的是被75℃热水浸泡60分钟不事先浸泡膨胀（实验四，8.0纳摩尔）和已被空气干燥10分钟后在75℃水中浸泡肿胀（实验一，
8.3纳摩尔）。豆浆制备中含有较高的过氧化脂质含量的是用95℃的热水浸泡肿胀（实验六，13.1纳摩尔），和大豆在相对湿度80-90%，温度75℃条件下蒸制10分钟（实验二，10.5纳摩尔）。这些研究结果表明，热处理在75℃或95℃时大豆过氧化脂质含量下降。由于 L2的活性，产生固氮酶的令人不愉快的气味，通过在70℃的热水中浸泡肿胀是之消除（马托巴等人，1985），在实验中热处理在75℃或95℃能够抑制这种酶的活性。
在实验三和实验五中，大豆在水中浸泡溶胀后加热得到的豆奶具有最低过氧化脂质含量，在实验一与实验二中，大豆在加热后浸泡肿胀得到的豆奶具有较高的过氧化脂质含量，在实验四中，溶胀过程是在加热过程中同时采取的。由此可见加热和浸泡大豆导致热量更容易散发，因而更容易抑制脂氧合酶或使失活。此外，由于在实验六中大豆浸泡肿胀后用热水匀浆制备的豆奶具有较高的过氧化脂质含量，它表示在适当的温度下与空气接触使酶的活性升高。
在所有上述发现的基础上，似乎大豆在75℃的热水中烫两分钟并在水中浸泡膨胀或在75℃相对湿度80-90%的条件下蒸制10分钟制得的豆浆的豆腥味相当于或者高于脂氧合酶缺乏的大豆制备的豆浆。
II. 豆乳含量，蛋白质和固体物质含量
热处理生产的豆奶的产量明显下降。特别是，大豆浸泡肿胀（实验六）在热水中匀浆后豆奶的提取率是对照组的70%是非常低的，大豆在75℃热水中加热60分钟后匀浆的是72.7%（实验四）。浸泡肿胀后在75℃热水中加热两分钟（实验五）的是89.3%是略微偏低的。其他大豆的产量略有降低，在97.5%和98.8%之间不等。因为对于实验六和实验四蛋白质含量（分别为40.4%和46.3%）和固体物质提取率（分别为38.0%和36.7%）致使豆浆产量大大降低，出现蛋白质变性和导致相关的不熔
化发生从而导致产率降低。导致实验五产率下降也是因为类似的原因。对于实验三中，其中固氮酶的活性被抑制到最大程度，豆浆产量、蛋白质含量、固体物质的含量与对照组中都大致相同，但在实验五中，有一种趋势的值是略微偏低的。因此，对于在75℃相对湿度80-90%条件下蒸制十分钟后浸泡肿胀的大豆制备的豆奶脂肪氧合酶的作用基本上被抑制，豆腥味也被最小化。
阿萨多等人（1989）发现脂肪氧化酶同功酶中，L2（马托巴等人，1985) 的活性也是产生令人不愉快的气味的重要原因，在70℃的热水中浸泡膨胀几乎可以完全消除。大村和武市（1990）报道，在70℃的热水中加热浸泡膨胀处理去皮的大豆5分钟可以抑制大豆产生的气味，而且豆浆固形物的含量的损失也可降低大约在10%左右。本研究的结果与这些报道一致。这些热水浸泡的方法在小型和中型的工厂中很容易实现，因为它们并不需要专门的设备。因为本研究方法中所涉及的热处理需要在潮湿条件下进行，所以阳离子与蒸汽消毒或隧道式蒸汽加热系统是可以实现的。 用热水（98℃）热烫浸泡肿胀后用水冷却制备的豆浆，对其脂质过氧化物含量、蛋白质和固形物的提取率进行测定。用1克大豆不用开水热烫制备的豆浆的过氧化脂质含量为21.0纳摩尔。但是在热水中烫一下，含量逐渐下降至20s 。对于未经处理的大豆大豆脱皮30秒准备的过氧化脂质含量急剧下降约23。然而，似乎没有进一步的变化。这些研究表明，脱皮的大豆在沸水中浸泡溶胀后的脂肪氧化酶被抑制或阻止。用几乎相同的方法的过氧化脂质含量、蛋白质含量和固体物质的提取率降低。非加热大豆的蛋白质提取率是78.7%，热烫20秒后是75.1%。热烫30秒后是70.2%。同样，非脱皮大豆固体物质的提取率为67.5%，热烫分别为20秒和30秒之后为64.8%和61.0%。
根据以上的结果，可以推断，如果正常的大豆浸泡肿胀后脱皮在沸水中处理30秒，过氧化脂质的含量会显著地降低但不会使蛋白质或固体物质的含量降低，从而减少豆腥味。
大豆在沸水中烫30秒制备的豆浆的过氧化脂质含量与所有脂氧合酶缺失大豆（4.7纳摩尔）制备的豆浆含量相差不大，但高于大豆在75℃相对湿度80-90%（2.8纳摩尔）条件下的过氧化脂质含量。然而，蛋白质提取率（70.2%）和固体物质提取率（61.1%）几乎一致。通过常规方法制备的豆奶蛋白质提取率和固体物质提取率分别为78.5%和67.1%。从而证实了经过蒸制处理的豆奶蛋白质提取率约8%，固体物提取率约5-6%。
因此很显然这两种加工方法致使正常的大豆过氧化脂质含量降低到与脂氧合酶缺乏大豆的相同水平或者比其更低。然而，我们也确定了蛋白质和固体物质的提取率略有降低。为考虑过氧化脂质含量的影响，在75℃相对湿度80-90%的条件下处理10分钟是一个简单而又优良的处理办法。
有一份报告指出，在70℃的热水中浸泡肿胀去皮的大豆5分钟豆浆固体物质的损失将被抑制到10%（大村和武市，1990），但在目前的研究当中其结果表现为一个略低的值。这种差别可能是由于加热方法或者加热的持续时间不同所导致，所以通过调价加工条件有可能达到提高提取率的目的。
对蛋奶布丁、巴伐利亚奶油和安尼豆腐制备的豆浆的豆腥味进行感官评价。含有豆浆的甜品在很大程度上都有略强的豆腥味（2.13-1.67）。甜点豆腥味的等级显示热处理的方法使豆腥味显著降低（3.47-3.80）。
上述结果表明，豆奶的豆腥味能够通过热水中浸泡肿胀30秒得以显著的减小。
附件2：外文原文
Effect of Heat Treatment on the Lipid Peroxide Content and Aokusami (Beany Flavor) of Soymilk
With the objective of minimizing aokusami (beany flavor), which is an undesirable aspect of soymilk flavor, we studied the effects of heating on lipid peroxide content, a factor contributing to the beany flavor. We also prepared various desserts containing soymilk using this heating process, and evaluated the effects of heating by sensory test. The lipid peroxide content of soymilk prepared from soaked and swollen soybeans steamed at 75'C in a relative humidity of 80-90% for 10 minutes was substantially lower than that in soymilk prepared from soybeans which lacked lipoxygenase and was 14% or less that of non-heat-treated soybeans. Additionally, the lipid peroxide content of soymilk prepared by blanching soaked and swollen soybeans in boiling water for 30 seconds was comparable to that found in soymilk prepared from lipoxygenase-lacking soybeans. The beany flavor of custard pudding, Bavarian cream, and Annin tofu prepared with soymilk obtained from heat-treated soybeans was significantly improved.
Keywords: soy bean, soymilk, Iipid peroxide, beany flavor.
Soybeans have long played a pivotal role in the food culture of Japanese people as a foodstuff with a high nutri- tive value. Recent research has shown that soybean protein has a cholesterol-lowering effect (Anderson et al., 1995), that soybean saponin has anticancer activity (Kennedy, 1995), and that soybean isoflavones have inhibitory effects on breast cancer and prostate cancer (Peterson & Bernes, l 99 1 ; Peterson G & Bernes S, 1 993) as wel] as a preven- tative effect on osteoporosis (Tsuchida et al., 1999). Given the above, processed foods made from soybeans are valued as a source of isoflavones. Soybeans are used in numerous foods, including tofu, natto, miso, soy sauce, and soymilk. Soymilk is consumed as a beverage, and is also used as an ingredient in the making of jellies, custard puddings, and other desserts. However, the distinctive aokusami (beany flavor) produced by lipoxygenase has a major impact on consumer preference. Minimizing the beany flavor is there- fore a key challenge in widening the use of soymilk.
Several methods have been proposed for deactivating lipoxygenase: the hot water-added grinding method (Echigo et al., 1991 ), in which soybeans are soaked in hot water at 70'C and then homogenized in hot water at 95'C; the blanching method in hot water at 99.3'C (Seth & Nath, 1 988); and the microwave heating method (Wang & Toledo, 1987). However, all these methods share the problems of heating-induced insolubilization of protein and an associ- ated decrease in protein extraction rate (Ediriweera et al., 1 987). Omura and Takechi ( 1990) proposed heating soaked and swollen, peeled soybeans in hot water at 70'C for 5 min. However, because the peeling process is associated with detachment of the hypocotyls (Endo et al., 2003a), this process is unsuitable for the preparation of raw mate- rials for high-isoflavone soymilk.
The present research was performed with the objective of minimizing aokusami (beany flavor), which is an unde- sirable aspect of the flavor of soymilk and other soymilk- related drinks. We studied the effects of heating on lipid peroxide content, which contributes to the beany flavor, and we prepared desserts made with soymilk
processed in this manner to investigate its effects on flavor.
Materials and Methods
Test soybeans The following soybean varieties tested were grown, screened, and dried at the Fukushima Prefecture Agricultural Experiment Station: Suzuyutaka, Tohoku 126 (high-isoflavone soybean, Endo et al., 2003b), Tohoku 135 (lipoxygenase-lacking soybean; hereafter, Iipoxygenaselacking soybean), Tohoku 139 (low-allergen soybean strain; hereafter, Iow-allergen soybean), Shinanokuro (black soybean), Aomame 4 (blue soybean), and commercially- available lchihime (Tochigi Prefecture-origin; Iipoxyge- nase-lacking soybean).
Soybean heat-treatment method and soymilk prepara- tion Suzuyutaka was used as the raw material.
Control group: Soybeans were soaked and swollen in water at 20'C for 16 h, and soymilk was then prepared using the heat-squeezing method with the addition of water (6: I , water weight: soybean weight) (Endo et al., 2003a, similarly hereafter).
Test- I : Soybeans were air-dried for 10 min at 75'C (DK- 600T incubator; Hitachi Corp.), rinsed with water, and soymilk was then prepared by the same method as that described for the control group.
Test-2: Soybeans were steamed for 10 min at 75'C in a relative humidity of 80-90% (MTH-4400 constant tem- perature and humidity chamber; Sanyo) and rinsed with water. Soymilk was then prepared by the same method as that described for the control group.
Test-3: Soybeans that had been soaked and swollen in water for 16 h at 20'C were steamed for 10 min at 75'C in a relative humidity of 80-90% and rinsed with water, after which soymilk was prepared using the heat-squeezing method with the addition of water (6:1, water weight soybean weight).
Test-4: Soybeans were heated for 60 min in hot water at 750C and rinsed with water, after which soymilk was prepared using the heat-squeezing method with the addition of water (6: 1, water weight: soybean weight).
Test-5: Soybeans that had been soaked and swollen for 16 h in water at 20'C were blanched for 2 min in hot water (10:1, water weight: soybean weight) at 750C, and then rinsed with water, after which soymilk was prepared using the heat-squeezing method with the addition of water (6: I , water weight : soybean weight).
Test-6: Soymilk was prepared using the same method as that described for the control group, except that the soybeans were homogenized with hot water at 95'C.
The Suzuyutaka variety of soybeans was used for this test. Soybeans that had been soaked and swollen for 16 h at 20*C were blanched in boiling water for l0-40 s, and soymilk was then prepared using the heat-squeezing method with a 6-fold volume of water added.
Measurement of lipid peroxide content To 0.5 g of 32-mesh or finer soybean powder ground in a compact milling machine (AS One Corporation; Wonder Blender WB- I ), soymilk, or each of the soymilk desserts was added 10 mL of distilled water, and the mixture was ice-cooled while being homogenized for I min using a Polytron homog- enizer. The homogenate was allowed to stand for 60 min at 4'C, after which the lipid peroxide content was assayed by the DETBA (1,3-diethyl-2-thiobarbituric acid) method (Suda et al., 1994).
Preparation and sensory evaluation of soymilk desserts Desserts were made using soymilk prepared from Tohoku 126 soybeans, and a sensory evaluation of the beany flavor was undertaken. Using the heat-squeezing method with a 6-fold volume of water added, soymilk was prepared from soybeans blanched in boiling water (1000C) for 30 s after being soaked and swollen in water at 20'C for 16 h. Desserts were prepared using standard recipes, with milk partly replaced with soymilk (Table 1). Pudding was made using pudding mix (Nisshin Foods), Bavarian cream using Bavarian cream mix (Nisshin Foods), and Annin tofu using Annin tofu mix (Heichinsei) (Table 1).
Sensory evaluation was performed using a five-point rating scale (1: Strong; 2: Moderately strong; 3: Weak; 4: Almost none; 5: None whatsoever) to score the beany flavor of soymilk (Furukawa, 1994). Panelists comprised 15 staff members from the Aizu-Wakamatsu Technical Support Center (ages 25=56 years; 12 men and 3 women). Sensory evaluation was repeated twice and the mean scores were determined. Differences between samples were tested for significance using two-way ANOV A (Furukawa, 1994). The extraction rates of protein and solid matter in soymilk were measured according to a previously described method (Endo et al., 2003a).
Results and Discussion
The lipid peroxide content of normal soybeans (soybeans with lipoxygenase activity) ranged from 63.5 to 83.6 nmol, with a mean value of 76.2 nmol. The soybean variety with the lowest content was Shinanokuro and that with the highest content was Suzuyutaka. For lipoxygenase-1acking varieties, there was very little difference in lipid peroxide content; 23.6 nmol and 29.8 nmol for Tohoku 135 and lchihime, respectively. The mean content for these varieties was 26.7 nmol, approximately 35% of the content measured in normal soybeans.
The lipid peroxide content of soymilk showed the dif- ferences of a similar trend as for unprocessed soybeans. The lipid peroxide content of soymilk produced from normal soybeans ranged from 14.4 to 2 1 .3 nmol, with a mean value of 18.4 nmol. The mean lipid peroxide content of soymilk produced from lipoxygenase-1acking soybeans was 4.7 nmol, about 26% of that of normal soybeans. These results are almost identical to those obtained in previous research
(Furuta et al., 1996).
It has been reported that the content of n-hexanal, the major constituent of the beany flavor of soymilk, is directly proportional to that of lipid peroxide (Furuta et al., 1996), and that the beany flavor of soymilk prepared from all lipoxygenase-lacking soybeans is less than that of soymilk made from normal soybeans (Torres-Penaranda et al., 1998). Given these results, it was concluded that a soymilk with minimal beany flavor can be prepared if the lipid peroxide content is approximately 5 nmol/g.
i. Lipid peroxide content
The lipid peroxide content per gram of soymilk in the control group was 21.3 n mol. The lipid peroxide content of heat-treated soybeans was appreciably lower, and differed according to treatment method. Soymilks with the lowest lipid peroxide content were those prepared from soybeans that had been steamed for 10 min at 75'C in a relative humidity of 80-90(~o after being soaked and swollen in water (Test-3, 2.8 n mol), and
中英文翻译
(文档含英文原文和中文翻译)
附件1：翻译译文
热处理对豆奶（豆腥味）过氧化
脂质含量的影响
豆腥味是导致豆奶风味不理想的重要因素，为了以最大限度的降低豆奶的豆腥味，我们研究了热处理对过氧化脂质的影响，是影响豆腥味的一个重要因素。我们还以豆奶为原料并在制作过程中使用加热工序制备了各种甜点，从而通过感官实验来评价加热对其的影响。经过浸泡和在75℃热处理的肿涨的大豆在相对湿度80-90％处理十分钟的过氧化脂质的含量比大豆中缺乏脂氧合酶和14％或更少的热处理的大豆制备出的豆奶的过氧化脂质含量要大大降低。此外，设计热烫浸泡和肿胀的大豆在沸水中处理了30秒的豆奶的过氧化脂质含量可以与缺失脂肪氧合酶的大豆制作出的豆奶过氧化脂质含量相媲美。蛋奶布丁，巴伐利亚奶油以及经过热处理的大豆制作出的豆腐其中的豆腥味都得到了显著的改善。
关键词：大豆 豆奶 过氧化脂质 豆腥味
大豆长期以来都是作为高营养食品代名词在日本人的饮食文化中具有具足轻重的作用。最近的研究表明，大豆蛋白具有降低胆固醇的作用（爱德森等人，1995），大豆皂苷具有抗癌活性（肯尼迪，1995), 以及大豆异黄酮对乳腺癌和前列腺癌具有一定的抑制作用（彼得森&贝尔内斯,1991; 彼得森G&贝尔内斯S ，1993），以及对于骨质疏松症（土田等人，1999）具有一定的预防作用。根据以上情况可知，由大豆制成的加工食品的价值就是作为人体异黄酮的来源。大豆被用于很多的食品中，包括豆腐，纳豆，味精，酱油，豆浆。豆奶作为一种可利用的饮料，可以广泛应用于果冻，蛋奶布丁等甜品的制作原料。然而，脂肪氧合酶产生的独特的豆腥味对消费者的喜好产生了重大的影响。因此尽可能的减少豆腥味是能够使豆浆脱颖而出并广泛推广的关键性的挑战。
有几种用于激活脂肪氧合酶的方法已经被提出：温水处理研磨的方法（越后等，1991），其中，大豆在70℃热水中浸泡，然后用95℃的热水进行匀浆; 热烫（赛斯&纳特，1988）的方法，用99.3℃的热水进行处理，以及微波加热的方法（王&托莱多，1987）。然而，所有的这些方法都存在加热引起的不溶性蛋白质以及蛋白质提取率的下降（爱德威亚等，1987）的问题。欧姆拉和客市（1990）提出的把去皮黄
豆在热水中70℃5分钟使黄豆加热浸泡发胀。然而，由于在剥离的过程中与下胚轴的分离有关（恩多等人，2003），所以这个过程不适合于原料中含有高异黄酮的豆奶的制备。进行本次研究的目的是以最大限度的减少豆腥味为目标，这是影响豆浆以及豆浆相关的饮料味道的重要方面。我们研究了加热对有助于豆腥味产生的过氧化脂质含量的影响，我们准备自制甜品用这种方法进行处理从而探究其对豆制品风味的影响。
材料和方法
对以下大豆品种进行测试生长，筛选，并在福岛县农业试验站风干的大豆品种：东北126（高异黄酮大豆，恩多等人，2003b ），东北135（脂氧合酶缺失大豆，此后，固氮酶缺失大豆），东北139（低过敏源大豆品系，此后，低过敏原大豆），黑豆，青豆（青大豆）和市售大豆（枥木县产，核苷酸酶缺乏大豆）。
大豆热处理和豆奶制样被用作实验原料。
对照组：大豆在20℃水中浸泡16小时，以及添加水（6:1，水的重量:大豆的重量）然后进行热挤压的方法处理（恩多等人，2003，下同）。
试验一：大豆在75℃条件下进行空气干燥10分钟（DK-600T 培养箱，日立公司）用水漂洗，然后通过相同的方法制备豆浆如对照组所述。
实验二：大豆在相对湿度80-90%，温度75℃（MTH-4400恒定温度和湿度室中，三洋）蒸制10分钟之后并用水冲洗。然后通过相同的方法制备豆浆如对照组所述。 实验三：大豆需在20℃水中浸泡膨胀16小时，然后于75℃相对湿度80-90%条件下蒸制10分钟之后用水冲洗，与另外的水（6:1,水含量:大豆含量）通过热挤压法制备豆奶。
实验四：大都在75℃的热水中加热处理60分钟并用水冲洗，然后，与另外的水（6:1，水的重量:大豆的重量）用热挤压的方法制备豆奶。
实验五：大豆在20℃水中浸泡肿胀16小时，并在75℃热水（10:1，水的重量:大豆的重量）中烫2分钟并用水冲洗，然后在添加水（6:1，水的重量:大豆的重量）用热挤压的方法制备豆奶。
实验六：豆奶的制备与对照组的描述运用的是相同的方法，而其中不同的是大豆用95℃的热水进行匀浆。
多种品种的大豆被用于该实验，已经被20℃的水浸泡肿胀16小时的大豆在沸水中烫10-40秒，再准备以6倍体积的水加入用热挤压的方法制备豆奶。
测定过氧化脂质的含量为将0.5克32目或者更细的大豆粉末在一个紧凑的铣床（AS One 公司，奇迹搅拌机WB-1), 豆奶或者每豆奶甜品中加入十毫升蒸馏水，并将该混合物用兵冷却均化。将匀浆液静置60分钟到4之后，运用DETBA （1,3 - 二乙基-2 - 硫代巴比妥酸）方法（Suda 等人，1994）对过氧化脂质的含量进行测定。
对利用东北大豆126制成的豆浆甜品进行制备和感官评价，对豆腥味进行的一个感官评价。大豆在20℃的水中浸泡膨胀16小时后在沸水中烫（100℃）30秒，然后添加6倍体积的水并用热挤压的方法制备豆奶。甜品使用标准配方进行制备的，只是用豆奶来替换牛奶。布丁用布丁混合物（日清食品），巴伐利亚奶油采用巴伐利亚奶油混合物（日清食品），豆腐用豆腐混合物。
感官评价是采用五点量表（1：强;2:中等强度;3弱；4：几乎没有；5：完全没有）来区分豆浆的豆腥味（古河，1994）。小组成员包括来自会津若松技术支持中心（25岁到56岁；12男和3女）的15名工作人员。感官评价重复两次，测定结果为平均值。使用双因素方差分析对样本之间的差异进行了测试。蛋白质和豆浆中固体物质的提取率根据先前描述的方法（恩多等人，2003年）进行测定。
结果与讨论
正常的大豆（黄豆与脂氧合酶的活性）的过氧化脂质含量介于63.5到83.6纳摩尔，取76.2纳摩尔的平均值。大豆品种最低含量的是Shinanokuro 和最高含量的是Suzuyutaka 。对于脂氧合酶缺乏的品种为东北135和lchihime ，其过氧化脂质含量的差异很小为23.6纳摩尔和29.8纳摩尔。这些品种的平均含量为26.7纳摩尔，在正常的大豆中测的含量约35%。
作为未加工的大豆，其豆浆过氧化脂质含量的差异表现出一个类似的趋势。豆奶生产中的过氧化脂质含量从大豆的正常范围14.4到21.3纳摩尔，取平均值18.4纳摩尔。大豆生产中平均过氧化脂质含量来自脂氧合酶缺乏大豆为4.7纳摩尔，大约是正常大豆水平的26%。这些在以往的研究中获得的结论几乎是相同的（古田等人，1996）。
正己醛的含量是豆浆豆腥味的主要成分这一观点已经被报道，它的含量与过氧化脂质的含量成正比（古田等人，1996），并且所有脂氧合酶缺乏大豆所制备的豆浆产生的豆腥味小于正常大豆制备的豆浆（托雷斯-佩尼亚兰达等人，1998）。鉴于这些结果，可以得出结论最小的豆腥味的豆奶可以以过氧化脂质含量约5纳摩尔/克来制备。
I. 过氧化脂质的含量
对照组的豆浆过氧化脂质的含量为没克21.3纳摩尔。根据处理方法的不同热处理大豆过氧化脂质含量明显降低。制备的豆奶中具有最低过氧化脂质含量分别为蒸制10分钟，在75℃80-90的相对湿度处理加上浸泡和在水中膨胀的大豆（实验三，2.8纳摩尔），和在加热的热水中处理两分钟，在75℃浸泡和在水中溶胀的大豆（实验五，3.3纳摩尔）。在这两组中过氧化脂质的含量明显低于脂氧合酶缺乏的大豆制备的豆奶。下一组最低过氧化脂质含量的是被75℃热水浸泡60分钟不事先浸泡膨胀（实验四，8.0纳摩尔）和已被空气干燥10分钟后在75℃水中浸泡肿胀（实验一，
8.3纳摩尔）。豆浆制备中含有较高的过氧化脂质含量的是用95℃的热水浸泡肿胀（实验六，13.1纳摩尔），和大豆在相对湿度80-90%，温度75℃条件下蒸制10分钟（实验二，10.5纳摩尔）。这些研究结果表明，热处理在75℃或95℃时大豆过氧化脂质含量下降。由于 L2的活性，产生固氮酶的令人不愉快的气味，通过在70℃的热水中浸泡肿胀是之消除（马托巴等人，1985），在实验中热处理在75℃或95℃能够抑制这种酶的活性。
在实验三和实验五中，大豆在水中浸泡溶胀后加热得到的豆奶具有最低过氧化脂质含量，在实验一与实验二中，大豆在加热后浸泡肿胀得到的豆奶具有较高的过氧化脂质含量，在实验四中，溶胀过程是在加热过程中同时采取的。由此可见加热和浸泡大豆导致热量更容易散发，因而更容易抑制脂氧合酶或使失活。此外，由于在实验六中大豆浸泡肿胀后用热水匀浆制备的豆奶具有较高的过氧化脂质含量，它表示在适当的温度下与空气接触使酶的活性升高。
在所有上述发现的基础上，似乎大豆在75℃的热水中烫两分钟并在水中浸泡膨胀或在75℃相对湿度80-90%的条件下蒸制10分钟制得的豆浆的豆腥味相当于或者高于脂氧合酶缺乏的大豆制备的豆浆。
II. 豆乳含量，蛋白质和固体物质含量
热处理生产的豆奶的产量明显下降。特别是，大豆浸泡肿胀（实验六）在热水中匀浆后豆奶的提取率是对照组的70%是非常低的，大豆在75℃热水中加热60分钟后匀浆的是72.7%（实验四）。浸泡肿胀后在75℃热水中加热两分钟（实验五）的是89.3%是略微偏低的。其他大豆的产量略有降低，在97.5%和98.8%之间不等。因为对于实验六和实验四蛋白质含量（分别为40.4%和46.3%）和固体物质提取率（分别为38.0%和36.7%）致使豆浆产量大大降低，出现蛋白质变性和导致相关的不熔
化发生从而导致产率降低。导致实验五产率下降也是因为类似的原因。对于实验三中，其中固氮酶的活性被抑制到最大程度，豆浆产量、蛋白质含量、固体物质的含量与对照组中都大致相同，但在实验五中，有一种趋势的值是略微偏低的。因此，对于在75℃相对湿度80-90%条件下蒸制十分钟后浸泡肿胀的大豆制备的豆奶脂肪氧合酶的作用基本上被抑制，豆腥味也被最小化。
阿萨多等人（1989）发现脂肪氧化酶同功酶中，L2（马托巴等人，1985) 的活性也是产生令人不愉快的气味的重要原因，在70℃的热水中浸泡膨胀几乎可以完全消除。大村和武市（1990）报道，在70℃的热水中加热浸泡膨胀处理去皮的大豆5分钟可以抑制大豆产生的气味，而且豆浆固形物的含量的损失也可降低大约在10%左右。本研究的结果与这些报道一致。这些热水浸泡的方法在小型和中型的工厂中很容易实现，因为它们并不需要专门的设备。因为本研究方法中所涉及的热处理需要在潮湿条件下进行，所以阳离子与蒸汽消毒或隧道式蒸汽加热系统是可以实现的。 用热水（98℃）热烫浸泡肿胀后用水冷却制备的豆浆，对其脂质过氧化物含量、蛋白质和固形物的提取率进行测定。用1克大豆不用开水热烫制备的豆浆的过氧化脂质含量为21.0纳摩尔。但是在热水中烫一下，含量逐渐下降至20s 。对于未经处理的大豆大豆脱皮30秒准备的过氧化脂质含量急剧下降约23。然而，似乎没有进一步的变化。这些研究表明，脱皮的大豆在沸水中浸泡溶胀后的脂肪氧化酶被抑制或阻止。用几乎相同的方法的过氧化脂质含量、蛋白质含量和固体物质的提取率降低。非加热大豆的蛋白质提取率是78.7%，热烫20秒后是75.1%。热烫30秒后是70.2%。同样，非脱皮大豆固体物质的提取率为67.5%，热烫分别为20秒和30秒之后为64.8%和61.0%。
根据以上的结果，可以推断，如果正常的大豆浸泡肿胀后脱皮在沸水中处理30秒，过氧化脂质的含量会显著地降低但不会使蛋白质或固体物质的含量降低，从而减少豆腥味。
大豆在沸水中烫30秒制备的豆浆的过氧化脂质含量与所有脂氧合酶缺失大豆（4.7纳摩尔）制备的豆浆含量相差不大，但高于大豆在75℃相对湿度80-90%（2.8纳摩尔）条件下的过氧化脂质含量。然而，蛋白质提取率（70.2%）和固体物质提取率（61.1%）几乎一致。通过常规方法制备的豆奶蛋白质提取率和固体物质提取率分别为78.5%和67.1%。从而证实了经过蒸制处理的豆奶蛋白质提取率约8%，固体物提取率约5-6%。
因此很显然这两种加工方法致使正常的大豆过氧化脂质含量降低到与脂氧合酶缺乏大豆的相同水平或者比其更低。然而，我们也确定了蛋白质和固体物质的提取率略有降低。为考虑过氧化脂质含量的影响，在75℃相对湿度80-90%的条件下处理10分钟是一个简单而又优良的处理办法。
有一份报告指出，在70℃的热水中浸泡肿胀去皮的大豆5分钟豆浆固体物质的损失将被抑制到10%（大村和武市，1990），但在目前的研究当中其结果表现为一个略低的值。这种差别可能是由于加热方法或者加热的持续时间不同所导致，所以通过调价加工条件有可能达到提高提取率的目的。
对蛋奶布丁、巴伐利亚奶油和安尼豆腐制备的豆浆的豆腥味进行感官评价。含有豆浆的甜品在很大程度上都有略强的豆腥味（2.13-1.67）。甜点豆腥味的等级显示热处理的方法使豆腥味显著降低（3.47-3.80）。
上述结果表明，豆奶的豆腥味能够通过热水中浸泡肿胀30秒得以显著的减小。
附件2：外文原文
Effect of Heat Treatment on the Lipid Peroxide Content and Aokusami (Beany Flavor) of Soymilk
With the objective of minimizing aokusami (beany flavor), which is an undesirable aspect of soymilk flavor, we studied the effects of heating on lipid peroxide content, a factor contributing to the beany flavor. We also prepared various desserts containing soymilk using this heating process, and evaluated the effects of heating by sensory test. The lipid peroxide content of soymilk prepared from soaked and swollen soybeans steamed at 75'C in a relative humidity of 80-90% for 10 minutes was substantially lower than that in soymilk prepared from soybeans which lacked lipoxygenase and was 14% or less that of non-heat-treated soybeans. Additionally, the lipid peroxide content of soymilk prepared by blanching soaked and swollen soybeans in boiling water for 30 seconds was comparable to that found in soymilk prepared from lipoxygenase-lacking soybeans. The beany flavor of custard pudding, Bavarian cream, and Annin tofu prepared with soymilk obtained from heat-treated soybeans was significantly improved.
Keywords: soy bean, soymilk, Iipid peroxide, beany flavor.
Soybeans have long played a pivotal role in the food culture of Japanese people as a foodstuff with a high nutri- tive value. Recent research has shown that soybean protein has a cholesterol-lowering effect (Anderson et al., 1995), that soybean saponin has anticancer activity (Kennedy, 1995), and that soybean isoflavones have inhibitory effects on breast cancer and prostate cancer (Peterson & Bernes, l 99 1 ; Peterson G & Bernes S, 1 993) as wel] as a preven- tative effect on osteoporosis (Tsuchida et al., 1999). Given the above, processed foods made from soybeans are valued as a source of isoflavones. Soybeans are used in numerous foods, including tofu, natto, miso, soy sauce, and soymilk. Soymilk is consumed as a beverage, and is also used as an ingredient in the making of jellies, custard puddings, and other desserts. However, the distinctive aokusami (beany flavor) produced by lipoxygenase has a major impact on consumer preference. Minimizing the beany flavor is there- fore a key challenge in widening the use of soymilk.
Several methods have been proposed for deactivating lipoxygenase: the hot water-added grinding method (Echigo et al., 1991 ), in which soybeans are soaked in hot water at 70'C and then homogenized in hot water at 95'C; the blanching method in hot water at 99.3'C (Seth & Nath, 1 988); and the microwave heating method (Wang & Toledo, 1987). However, all these methods share the problems of heating-induced insolubilization of protein and an associ- ated decrease in protein extraction rate (Ediriweera et al., 1 987). Omura and Takechi ( 1990) proposed heating soaked and swollen, peeled soybeans in hot water at 70'C for 5 min. However, because the peeling process is associated with detachment of the hypocotyls (Endo et al., 2003a), this process is unsuitable for the preparation of raw mate- rials for high-isoflavone soymilk.
The present research was performed with the objective of minimizing aokusami (beany flavor), which is an unde- sirable aspect of the flavor of soymilk and other soymilk- related drinks. We studied the effects of heating on lipid peroxide content, which contributes to the beany flavor, and we prepared desserts made with soymilk
processed in this manner to investigate its effects on flavor.
Materials and Methods
Test soybeans The following soybean varieties tested were grown, screened, and dried at the Fukushima Prefecture Agricultural Experiment Station: Suzuyutaka, Tohoku 126 (high-isoflavone soybean, Endo et al., 2003b), Tohoku 135 (lipoxygenase-lacking soybean; hereafter, Iipoxygenaselacking soybean), Tohoku 139 (low-allergen soybean strain; hereafter, Iow-allergen soybean), Shinanokuro (black soybean), Aomame 4 (blue soybean), and commercially- available lchihime (Tochigi Prefecture-origin; Iipoxyge- nase-lacking soybean).
Soybean heat-treatment method and soymilk prepara- tion Suzuyutaka was used as the raw material.
Control group: Soybeans were soaked and swollen in water at 20'C for 16 h, and soymilk was then prepared using the heat-squeezing method with the addition of water (6: I , water weight: soybean weight) (Endo et al., 2003a, similarly hereafter).
Test- I : Soybeans were air-dried for 10 min at 75'C (DK- 600T incubator; Hitachi Corp.), rinsed with water, and soymilk was then prepared by the same method as that described for the control group.
Test-2: Soybeans were steamed for 10 min at 75'C in a relative humidity of 80-90% (MTH-4400 constant tem- perature and humidity chamber; Sanyo) and rinsed with water. Soymilk was then prepared by the same method as that described for the control group.
Test-3: Soybeans that had been soaked and swollen in water for 16 h at 20'C were steamed for 10 min at 75'C in a relative humidity of 80-90% and rinsed with water, after which soymilk was prepared using the heat-squeezing method with the addition of water (6:1, water weight soybean weight).
Test-4: Soybeans were heated for 60 min in hot water at 750C and rinsed with water, after which soymilk was prepared using the heat-squeezing method with the addition of water (6: 1, water weight: soybean weight).
Test-5: Soybeans that had been soaked and swollen for 16 h in water at 20'C were blanched for 2 min in hot water (10:1, water weight: soybean weight) at 750C, and then rinsed with water, after which soymilk was prepared using the heat-squeezing method with the addition of water (6: I , water weight : soybean weight).
Test-6: Soymilk was prepared using the same method as that described for the control group, except that the soybeans were homogenized with hot water at 95'C.
The Suzuyutaka variety of soybeans was used for this test. Soybeans that had been soaked and swollen for 16 h at 20*C were blanched in boiling water for l0-40 s, and soymilk was then prepared using the heat-squeezing method with a 6-fold volume of water added.
Measurement of lipid peroxide content To 0.5 g of 32-mesh or finer soybean powder ground in a compact milling machine (AS One Corporation; Wonder Blender WB- I ), soymilk, or each of the soymilk desserts was added 10 mL of distilled water, and the mixture was ice-cooled while being homogenized for I min using a Polytron homog- enizer. The homogenate was allowed to stand for 60 min at 4'C, after which the lipid peroxide content was assayed by the DETBA (1,3-diethyl-2-thiobarbituric acid) method (Suda et al., 1994).
Preparation and sensory evaluation of soymilk desserts Desserts were made using soymilk prepared from Tohoku 126 soybeans, and a sensory evaluation of the beany flavor was undertaken. Using the heat-squeezing method with a 6-fold volume of water added, soymilk was prepared from soybeans blanched in boiling water (1000C) for 30 s after being soaked and swollen in water at 20'C for 16 h. Desserts were prepared using standard recipes, with milk partly replaced with soymilk (Table 1). Pudding was made using pudding mix (Nisshin Foods), Bavarian cream using Bavarian cream mix (Nisshin Foods), and Annin tofu using Annin tofu mix (Heichinsei) (Table 1).
Sensory evaluation was performed using a five-point rating scale (1: Strong; 2: Moderately strong; 3: Weak; 4: Almost none; 5: None whatsoever) to score the beany flavor of soymilk (Furukawa, 1994). Panelists comprised 15 staff members from the Aizu-Wakamatsu Technical Support Center (ages 25=56 years; 12 men and 3 women). Sensory evaluation was repeated twice and the mean scores were determined. Differences between samples were tested for significance using two-way ANOV A (Furukawa, 1994). The extraction rates of protein and solid matter in soymilk were measured according to a previously described method (Endo et al., 2003a).
Results and Discussion
The lipid peroxide content of normal soybeans (soybeans with lipoxygenase activity) ranged from 63.5 to 83.6 nmol, with a mean value of 76.2 nmol. The soybean variety with the lowest content was Shinanokuro and that with the highest content was Suzuyutaka. For lipoxygenase-1acking varieties, there was very little difference in lipid peroxide content; 23.6 nmol and 29.8 nmol for Tohoku 135 and lchihime, respectively. The mean content for these varieties was 26.7 nmol, approximately 35% of the content measured in normal soybeans.
The lipid peroxide content of soymilk showed the dif- ferences of a similar trend as for unprocessed soybeans. The lipid peroxide content of soymilk produced from normal soybeans ranged from 14.4 to 2 1 .3 nmol, with a mean value of 18.4 nmol. The mean lipid peroxide content of soymilk produced from lipoxygenase-1acking soybeans was 4.7 nmol, about 26% of that of normal soybeans. These results are almost identical to those obtained in previous research
(Furuta et al., 1996).
It has been reported that the content of n-hexanal, the major constituent of the beany flavor of soymilk, is directly proportional to that of lipid peroxide (Furuta et al., 1996), and that the beany flavor of soymilk prepared from all lipoxygenase-lacking soybeans is less than that of soymilk made from normal soybeans (Torres-Penaranda et al., 1998). Given these results, it was concluded that a soymilk with minimal beany flavor can be prepared if the lipid peroxide content is approximately 5 nmol/g.
i. Lipid peroxide content
The lipid peroxide content per gram of soymilk in the control group was 21.3 n mol. The lipid peroxide content of heat-treated soybeans was appreciably lower, and differed according to treatment method. Soymilks with the lowest lipid peroxide content were those prepared from soybeans that had been steamed for 10 min at 75'C in a relative humidity of 80-90(~o after being soaked and swollen in water (Test-3, 2.8 n mol), and