玉米淀粉对大蒜中大蒜素的包合及其复合物的抑菌活性

以玉米淀粉和鲜大蒜为原料,尝试高速剪切混合制备淀粉-大蒜素复合物,并对其抑菌活性进行评价。结果表明,当高速剪切混合处理时间为40 min,大蒜(干基)/淀粉质量比为3:2时,复合物中大蒜素的含量为1.17±0.02μg/mg,包埋率为89.71%±1.20%。碘结合实验表明,淀粉与大蒜中的大蒜素通过主客体相互作用形成复合物。玉米淀粉经高速剪切混合处理后颗粒形态的变化不大,但是与大蒜共同处理后淀粉颗粒的形态发生较大的变化。形成复合物后淀粉的结晶度降低;淀粉复合物比大蒜粉具有较高的热稳定性。抑菌实验表明,复合物的抑菌活性良好,当大蒜(干基)与玉米淀粉质量比为3:2时,其对E.coli,S.aureus,B.subtilis和S.Typhimurium的抑菌圈直径分别为19.92±0.03、23.02±0.03、34.51±0.20、23.21±0.15 mm。淀粉-大蒜素复合物的形成,提高了大蒜素的生物活性。     

3种淀粉与大蒜中大蒜素所形成包合物的特征及其抑菌活性研究

分别选择玉米淀粉(CS)、马铃薯淀粉(PS)和高直链玉米淀粉(HAMS)为主体,大蒜在高速剪切混合处理过程中形成的大蒜素为客体,探讨了淀粉-大蒜素的包合物(CS-A、PS-A和HAMS-A)的形成条件及其理化性质和抑菌活性。结果表明,CS、PS和HAMS分别在淀粉与大蒜(干基)质量比为1:2、1:6、1:2,高速剪切混合处理40、60、40 min时,所制备的包含物中大蒜素的含量较高。碘结合实验表明,3种淀粉与大蒜素发生包合作用的强弱次序为HAMS-A>PS-A>CS-A。经高速剪切混合处理后所形成的包合物,淀粉颗粒体积溶胀,结晶度降低,没有呈现V型结晶结构。3种包合物热稳定性大小次序为HAMS-A>PS-A>CS-A。通过对3种包合物的抗菌活性评价表明,3种包合物抑菌活性大小次序为HAMS-A>PS-A>CS-A。该研究可为大蒜素的高效利用及淀粉基大蒜素微胶囊的开发提供技术支撑。     

马铃薯淀粉包埋脱除大蒜臭味

为了保护大蒜的活性成分和掩盖大蒜的不愉快气味,本研究采用研磨法利用马铃薯淀粉的螺旋结构对大蒜 的有机硫化合物进行包埋,以马铃薯淀粉、大蒜（干基）为原料,用包埋率和脱臭效果为指标优化其脱臭工艺,并 对样品进行结构表征。通过高效液相色谱法测定得到的最佳脱臭条件为：马铃薯淀粉与大蒜（干基）质量比3∶1, 研磨时间2.5 h,在此条件下,所得产品的包埋率为（90.63±1.11）%,感官鉴评得分95 分。通过扫描电子显微镜观 察可知,淀粉颗粒被破坏,呈现团聚结构;X射线衍射仪分析表明淀粉的结晶度降低,傅里叶变换红外光谱和热重 分析结果表明样品具有良好的稳定性;通过气相色谱-质谱联用分析可知,大蒜中11 种有机硫化合物的成分在样品 中被全部检出,说明研磨法能促进马铃薯淀粉包埋新鲜大蒜中的臭味物质,既保留大蒜中有机硫化合物又可以达到 脱臭的目的。     

五香牛肉鸡枞菌风味酱的研制

以鸡枞菌、牛肉和豆豉为主要原料,植物油、食用盐、五香粉、白糖、葱姜蒜等为辅料制作牛肉酱,以感官评分为评价指标,首先通过单因素、正交试验对影响酱品质的主料和辅料配方进行优化,然后以主料、辅料和淀粉为3个因素,采用响应面法对五香鸡枞菌牛肉风味酱配方进行优化研究。结果表明,最佳风味酱配方为鸡枞菌30.0%,牛肉26.7%、豆豉23.4%、植物油7.1%、葱姜蒜4.4%、白糖2.2%、食用盐2.8%、五香粉1.5%、淀粉1.9%。此优化条件下,感官得分为92.97分。鸡枞菌和牛肉香味浓郁,色泽较为鲜亮,酱体浓稠适中,营养丰富,方便即食。该产品的亚硝酸盐含量为2.3 mg/kg,所有指标均符合国家标准。     

药用菌物除味糖的配方优化

通过对亚砖红沿丝伞及银耳提取物除味作用的研究,可得知亚砖红沿丝伞食用乙醇提取物和银耳水提物均有明显的除味作用。以亚砖红沿丝伞、银耳这两种药用菌的有效提取物以及麦芽糖、食用胶等为原料,采用正交试验确定最佳配方,且采用高效液相色谱法测定其对大蒜臭味物质的脱除作用,最终研制出口感佳、咀嚼性好、甜度适宜、能够除去口中异味（大蒜异味）且对环境无污染的新型功能性糖。其最佳配方（质量分数）为麦芽糖50.0%、银耳水提物12.0%、麦芽糊精10.0%、白砂糖8.0%、奶粉7.0%、酸性变性淀粉4.0%、亚砖红沿丝伞食用乙醇提取物3.0%、打发蛋白3.0%、阿拉伯胶1.5%、薄荷粉0.8%、蔗糖酯0.7%。     

Characterization of lactic acid bacteria isolated from a Thai low-salt fermented fish product and the role of garlic as substrate for fermentation

Lactic acid bacteria (LAB) isolated from raw materials (fish, rice, garlic and banana leaves) and processed som-fak (a Thai low-salt fermented fish product) were characterized by API 50-CH and other phenotypic criteria. Lactococcus lactis subsp. lactis and Leuconostoc citreum were specifically associated with fish fillet and minced fish, Lactobacillus paracasei subsp. paracasei with boiled rice and Weisella confusa with garlic mix and banana leaves. In addition, Lactobacillus plantarum, Lactobacillus pentosus and Pediococcus pentosaceus were isolated from raw materials. A succession of aciduric, homofermentative lactobacillus species, dominated by Lb. plantarum/pentosus, was found during fermentation. In total, 9% of the strains fermented starch and 19% fermented garlic, the two main carbohydrate components in som-fak. The ability to ferment garlic was paralleled by a capacity to ferment inulin. An increased percentage of garlic fermenting strains was found during fermentation of som-fak, from 8% at day 1 to 40% at day 5. No starch fermenting strains were isolated during fermentation. Three mixed LAB cultures, composed of either starch fermenting Lc. lactis subsp. lactis and Lb. paracasei subsp. paracasei, or garlic fermenting Lb. plantarum and Pd. pentosaceus, or a combination of these strains were inoculated into laboratory prepared som-fak with or without garlic. In som-fak without garlic, pH was above 4.8 after three days, irrespective of addition of mixed LAB cultures. The starch fermenting LAB were unable to ferment som-fak and sensory spoilage occurred after three days. Fermentation with the combined mix of starch and garlic fermenting strains led to production of 2.5% acid and a decrease in pH to 4.5 in two days. The fermentation was slightly slower with the garlic fermenting strains alone. This is the first report describing the role of garlic as carbohydrate source for LAB in fermented fish products.     

玉米淀粉/蛋壳粉复合膜的制备及性能分析

以玉米淀粉（corn starch,CS）和蛋壳粉（eggshell powder,ESP）为主要成膜基材制备CS/ESP复合膜。研究CS质量浓度、ESP添加量、丙三醇（glycerol,Gly）添加量3 个因素对CS/ESP膜抗拉强度（tensile strength,TS）、断裂伸长率（elongation at break,EB）、水蒸气透过系数（water vapour permeability,WVP）和氧气透过率（oxygen permeability,OP）的影响。在此基础上采用主成分分析法对膜性能进行综合评价,并通过响应面法优化试验得到CS/ESP膜制备的最佳工艺参数,具体如下：CS质量浓度4.9 g/100 mL、Gly添加量49%（m/m）、ESP添加量1.9%（m/m）,对应CS/ESP膜的TS、EB、WVP和OP分别为4.97 MPa、109.12%、1.31×10－12 g/（cm·s·Pa）和1.19×10－5 cm3/（m2·d·Pa）。傅里叶变换红外光谱分析表明ESP和CS具有较好的相容性。X射线衍射和热重分析结果表明ESP的添加提高了CS/ESP膜的结晶度和热稳定性。扫描电子显微镜分析表明CS/ESP膜具有光滑的表面和断面形貌,没有明显的突起和腔。     

己酸酯淀粉的制备及其上浆性能

为开发适合疏水性纤维特别是聚乳酸纤维经纱上浆的变性淀粉浆料品种,以己酸酐(CA)为酯化剂,通过改变其用量制备了不同取代度的己酸酯淀粉(CS)。对CS颗粒结构进行了红外光谱分析,探究了己酸酯化变性对淀粉浆液性能、浆膜力学性能的影响。结果表明:经己酸酯化变性后,淀粉浆液的黏度热稳定性、淀粉对聚乳酸和涤纶纤维的黏附性及淀粉膜的断裂伸长率均得到了提升,膜的断裂强度有所降低;CS对2种纤维的黏附力,在取代度小于0.025时逐渐提高,且在0.025时取得最大值,然后随取代度增加而有所降低;CS膜的断裂伸长率随取代度增大而提高,断裂强度逐渐降低;CS浆液的黏度热稳定性逐渐降低,但均高于酸解淀粉。     

食品成分对淀粉糊性能的影响

用Ｂｒａｂｅｎｄｅｒ淀粉粘度仪研究分析了一些食品成分如食盐、蔗糖、柠檬酸以及琼脂等对玉米淀粉和玉米淀粉磷酸酯糊的粘度性质的影响，结果表明：柠檬酸、食盐、蔗糖、琼脂对玉米淀粉和玉米淀粉磷酸酯的粘度、老化都有影响。玉米淀粉经磷酸脂化后，老化速率减慢。食盐（浓度＜１％）、柠檬酸可减缓玉米淀粉的老化，却使酯化淀粉更易于老化。琼脂可以减缓玉米淀粉和玉米淀粉磷酸脂的老化，蔗糖却加速了这两种淀粉的老化。     

发酵紫苏粉对面包储藏品质影响的研究

试验将凝结芽孢杆菌和乳酸克鲁维酵母菌以比例为1:1、料水比为1:2.5、接种量为12%接种,在33℃环境下对紫苏粕固态发酵48 h后干燥,将发酵紫苏粉以一定的比例添加到面包面粉中,利用低场核磁、调制差式扫描量热仪等技术研究不同添加量的发酵紫苏粉对于储藏期面包水分分布与迁移规律、保水性、老化度、淀粉老化焓值以及脂肪氧化程度的影响。试验结果表明,随着发酵紫苏粉添加量的逐渐增大,面包失水、老化度、支链淀粉老化焓值和脂肪氧化程度(TBA)值呈下降趋势。发酵紫苏粉面包储藏期的保水性、老化度、淀粉老化焓值以及脂肪氧化程度指标均优于未加紫苏的空白组,最值分别降低了9.84%、55.56%、69.18%和58.18%;优于添加未发酵紫苏面包的对照组,最值分别降低了11.29%、12.5%、47.66%和7.35%。     

A switch point model for high-resolution moisture absorption isotherms of raw and pregelatinized starches

The goal of this work was to find or create a simple model of the experimental high-resolution water absorption isotherms, determined with the dynamic dewpoint isotherm method (DDI) for different forms of starch powder. The samples used were rice and cassava starches and their 1:1 mix, each in raw and pregelatinized forms. The adsorption isotherms were measured at both 25 and 35?°C temperatures for the water activity range 0.2–0.9. The results showed that the modern DDI method provided densely measured isotherms with consistent characteristics. In particular, a linear zone in the adsorption isotherms of starch powders can be identified and its extent estimated. It is also subjectively clear with the DDI resolution across all the samples tested. Aside from smallish distinction between raw and pregelatinized cases, the starches had very similar isotherms, which might represent a “generic starch flour isotherm”. This shape was very well fit by an initial linear segment and a final curved segment, with the critical transition at the switch point. The transition point results indicate that pregelatinization increases the demands on water barrier properties of the packaging.     

黑蒜粉膳食补充对环磷酰胺诱导BALB/c小鼠免疫功能的影响

目的：研究黑蒜粉对BALB/c小鼠的免疫调节作用。方法：采用环磷酰胺建立免疫抑制BALB/c小鼠动物模型,检测不同剂量（100、300、900 mg/kg）黑蒜粉对免疫抑制BALB/c小鼠脾脏、胸腺指数、脾淋巴细胞转化活性、迟发型变态反应能力、抗体生成细胞水平、半数溶血值、碳粒廓清速率、脾细胞中白细胞介素（interleukin,IL）-8和IL-12 mRNA表达水平等指标的影响。结果：与模型组相比,黑蒜粉低、中、高剂量组显著提高了小鼠的胸腺指数、抗体生成能力、脾淋巴细胞增殖能力以及脾细胞因子IL-8和IL-12 mRNA的表达量（P＜0.05）;中、高剂量组显著提升了小鼠的脾脏指数和迟发型变态反应能力（P＜0.05）;高剂量组则显著增强了小鼠的血清溶血素水平和单核-巨噬细胞吞噬活性（P＜0.05）。结论：黑蒜粉具有提高BALB/c小鼠免疫功能的作用。     

微胶囊化蒜粉的贮存稳定性

研究了微胶囊化蒜粉的贮存稳定性,并与蒜粉做了比较。结果表明,微胶囊化蒜粉贮存10个月后,硫代亚磺酸酯心材保留率仍在95%以上。DSC测定蒜粉的玻璃化转变温度为-2.9℃,微胶囊化蒜粉的玻璃化转变温度为112℃。采用SEM观察微胶囊化蒜粉内部与外部结构,发现微胶囊化蒜粉表面具有很好的完整性和致密性。因而微胶囊化蒜粉具有良好的贮存稳定性。     

蒜黄根膳食纤维提取工艺优化及其理化性质分析

为了优化蒜黄根膳食纤维提取工艺并分析提取的蒜黄根TDF理化性质,首先对酶解pH、酶解温度、酶解时间进行单因素实验;采用Box-Behnken试验设计,确定蒜黄根TDF提取的最佳工艺条件;最后对提取得到的蒜黄根TDF持水性、持油性、膨胀性、吸附葡萄糖和胆固醇能力以及抗氧化能力等理化性质进行分析。结果表明,蒜黄根TDF得率的最佳提取工艺条件为:酶解pH7.0、酶解温度62 ℃、酶解时间2.3 h。在最优条下蒜黄根TDF得率为72.47%±0.08%,与模型预测值72.59%基本一致。提取后的蒜黄根TDF持水性(8.63 g·g-1)、持油性(6.57 g·g-1)、膨胀性(6.27 mL·g-1)以及对葡萄糖和胆固醇的吸附能力(8.00 mg·g-1和10.52 mg·g-1)均显著高于蒜黄根粉(P<0.05)。然而蒜黄根TDF的抗氧化能力和总酚含量较蒜黄根粉显著降低(P<0.05)。因此,蒜黄根TDF可作为肉类和粮油类食品的优质添加剂,开发新型健康食品,提高蒜黄种植产业的资源利用率与产品附加值。     

5 种食品原料对高脂饮食诱导的肥胖大鼠肠道菌群和短链脂肪酸的影响

香蕉粉、魔芋精粉、抗性糊精、玉米淀粉以及左旋肉碱这5 种食品原料据报道都有减肥功能,但它们对肠道微生物和代谢产物的影响以及与肠道菌群相关的减肥机制的差异尚不清楚。本研究采用16S rRNA测序检测肥胖大鼠肠道内容物,并通过高效液相色谱法（high performance liquid chromatography,HPLC）测定粪便中短链脂肪酸的含量。结果显示：益生菌属Ruminococcus_2、Coprococcus_2和Ruminiclostridium_5分别在玉米淀粉、香蕉粉和抗性糊精组中富集。Spearman相关性分析和典型关联分析（canonical correlation analysis,CCA）结果表明,肠道微生物的变化与糖脂代谢相关的生化参数密切相关。以可溶性膳食纤维为主的原料（魔芋粉和抗性糊精）和以不可溶性膳食纤维（抗性淀粉）为主的原料（香蕉粉和玉米淀粉）对短链脂肪酸的产生能力贡献度相当,均优于左旋肉碱。5 种原料增殖肠道益生菌、抑制有害菌的效果依次为抗性糊精＞香蕉粉＞玉米淀粉＞魔芋精粉,增加短链脂肪酸含量的能力依次为香蕉粉＞抗性糊精＞玉米淀粉＞魔芋精粉,而左旋肉碱对肠道菌群和短链脂肪酸几乎没有什么影响。CCA结果显示,糖脂代谢生化指标与肠道微生物群落的相关程度为空腹血糖水平＞高密度脂蛋白胆固醇水平＞总胆固醇水平＞低密度脂蛋白胆固醇水平＞总甘油三酯水平。Spearman相关性分析表明Ruminococcus_2与丁酸含量呈正相关,Escherichia.Shigella与乙酸、丁酸和总短链脂肪酸含量呈正相关。     

Effects of fatty acids and calf starter form on intake,growth, digestion,and selected blood metabolites in male calves from 0 to 4 months of age

The objective of this research was to determine if form of calf starter (CS) and addition of a fatty acid blend (FA) influenced intake, growth, digestion, and indices of immune status and stress in calves from 0 to 4 mo of age. Male Holstein calves [n = 48; 41.9 kg of body weight (BW), standard error = 0.7; 2 to 3 d of age] were assigned to receive reconstituted whole milk powder [0.66 kg of dry matter (DM)/d to 39 d, then 0.33 kg of DM/d to weaning at 42 d] without or with added FA. Calf starters were textured (pellet, whole oats, whole corn) or pelleted and were offered for ad libitum consumption from 0 to 56 d, then blended with 5% chopped grass hay and fed from d 57 to 112. Starters contained 20% crude protein (CP) and 38 to 40% starch in the DM. From d 0 to 56, calves were housed individually. From d 57 to 112, calves were grouped into pens by treatment (n = 4/pen). Form of CS during the initial 56 d had no effect on intake or growth, though days with fluid feces (fecal score ≥2.5) were greater when calves were fed textured CS. Feeding FA during the initial 56-d increased average daily BW gain, gain-to-feed ratio, and change in hip width, and reduced the number of days calves were treated with antibiotics. During d 57 to 112, CS form had no effects on any performance measure. Adding FA to CS increased average daily BW gain and hip width change, and tended to improve efficiency of BW gain. Total-tract digestibility was estimated at 4, 6, and 8 wk with 5 calves per treatment, and at 10, 13, and 16 wk of age using pen (n = 3 per treatment) as the experimental unit. Feeding FA increased or tended to increase total-tract digestion of DM, organic matter, starch, neutral detergent fiber (NDF), acid detergent fiber (ADF), CP, and fat at one or more measurement periods. Calves fed a textured CS increased or tended to increase digestion of DM, organic matter, starch, sugar, NDF, ADF, and CP during wk 6 and 8. However, during the second 56-d phase, feeding textured CS reduced or tended to reduce digestion of DM, organic matter, starch, NDF, ADF, and fat during wk 13 and 16. Inclusion of FA in milk increased serum bactericidal activity before weaning. Serum haptoglobin concentration increased 3 d postweaning when calves were fed textured CS. Feeding FA improved animal health, digestion, and performance. Form of CS had few effects on animal performance.     

真空冷冻干燥大蒜粉对Fenton氧化体系中牦牛肉肌原纤维蛋白乳化特性的影响

用牦牛肉分离肌原纤维蛋白（myofibrillar protein,MP）和牦牛肉脂肪,向牦牛肉MP中分别添加质量分数为0%、0.2%、0.5%和1.0%的真空冷冻干燥（vacuum freeze-dried,VFD）大蒜粉,并构建Fenton氧化体系,测定牦牛肉MP在4 ℃环境中氧化12 h后的活性巯基含量、蛋白质溶解性、表面疏水性以及牦牛肉MP乳液的界面吸附蛋白百分比、乳液黏度、乳化活性、乳液稳定性（澄清指数、积分透光率、沉降速率）和微观结构,研究VFD大蒜粉对氧化体系中牦牛肉MP乳化特性的影响。结果表明：高添加量的VFD大蒜粉（0.5%、1.0%）能显著增强Fenton氧化体系中牦牛肉MP的乳化活性、乳化稳定性和乳液中油相分布均匀性（P＜0.05）;其中,添加0.5% VFD大蒜粉对Fenton氧化体系中牦牛肉MP的保护效果较强,能使牦牛肉MP的活性巯基含量增加1.55 倍、蛋白质溶解性增加19%、表面疏水性降低25.41%;添加1.0% VFD大蒜粉对Fenton氧化体系中牦牛肉MP的乳化特性改善作用较强,能使牦牛肉MP乳液的黏度增加1.02 倍、乳化活性增加49.80%,澄清指数、积分透光率以及沉降速率分别降低17.06%、37.44%和50.79%。说明VFD大蒜粉能显著改善Fenton氧化体系中牦牛肉MP的乳化特性,但作用效果与添加量相关,当添加质量分数为1.0%的VFD大蒜粉时,其改善作用较强。     

Physicochemical Properties,and Antioxidant and Antimicrobial Effects of Garlic and Onion Powder in Fresh Pork Belly and Loin during Refrigerated Storage

ABSTRACT: Pork loin and belly cuts were pumped to 110% of their original weight with solutions containing 5% of various ingredients (sodium ascorbate, garlic, and onion powder), and evaluated the physicochemical properties, and antioxidant and antimicrobial activities during refrigerated storage at 8 °C. The addition of garlic and onion powder tended to increase redness (a) and yellowness (b) in both the belly lean and loin with the exception of a few cases. Free fatty acid values in both pork belly and loin cuts were reduced with the addition of these ingredients, as compared to the control. Significant differences in peroxide values were observed in sodium ascorbate and garlic‐injected belly, and in sodium ascorbate and onion‐injected loin, as compared to the control. Thiobarbituric acid reactive substance values in the pork belly with garlic or onion powder were significantly lower than in the belly without these ingredients or with sodium ascorbate (P < 0.05). Total plate counts were lower in both the belly and loin containing garlic and onion powder, as compared to the control. In both the belly and loin cuts, the content of oxidative products (volatile compounds) was reduced with the addition of garlic and onion powder, particularly the aldehydes (hexanal). Overall, garlic and onion in enhanced meats showed an antioxidant activity as effective as that of sodium ascorbate and also an antimicrobial effect to inhibit the growth of total bacteria and Enterobacteriaceae.     

芭蕉芋淀粉对米粉理化性质及粉丝品质的影响

将芭蕉芋淀粉和籼米粉按照一定比例复配并制作粉丝,以复配粉的溶胀性质、热特性、糊化特性、流变学特性为理化性质测定指标,以粉丝的质构特性、蒸煮性质、感官品质为其质量评价指标,考察了芭蕉芋淀粉对米粉理化性质和粉丝品质的影响。结果表明：随着芭蕉芋淀粉添加量的增加,复配粉的直链淀粉含量、膨润力、峰值黏度、最低黏度、降落值、糊化焓、回生焓、回生度、弹性模量、黏性模量增加,而溶解度、最终黏度、回升值、糊化温度逐渐降低;米粉丝的硬度、弹性、黏附性、咀嚼性随芭蕉芋淀粉添加量的增加而增大。与纯籼米粉粉丝相比,复配粉米粉丝的筋道感和柔韧度增强,其光滑度却下降。综合考虑,添加2%～5%芭蕉芋淀粉的米粉丝品质最佳,具有很好的可接受性。     

Freeze-dried fresh onion powder prevents green discolouration (greening) in macerated garlic

Green discolouration (greening) of macerated garlic products is a major concern in the garlic-processing industry, and is caused by reactions between free amino acids and 2-propenyl 1-propenyl (2-Pe/1-Pe) thiosulphinates in the garlic. Efficacy of freeze-dried fresh onion powder that contains the active onion enzyme lachrymatory factor synthase (LFS) to prevent greening in processed garlic was evaluated. LFS converts 1-propenesulphenic acid to the volatile lachrymatory factor (LF). We hypothesised that this conversion would decrease the production of 2-Pe/1-Pe thiosulphinates, and thus, would reduce the subsequent discolouration of the garlic. Cooked onion powder added to fresh garlic, which was equivalent to adding crude 1-PeCSO, resulted in intensified green discolouration and increased 2-Pe/1-Pe thiosulphinate levels. On the other hand, fresh onion powder added to fresh garlic (0.5 g powder to 100 g fresh garlic) prevented greening and decreased the 2-Pe/1-Pe thiosulphinate levels. Similarly, a crude onion enzyme solution prevented greening in a garlic homogenate. The 2-propenyl 2-propenyl thiosulphinate (allicin) content was inconsistently altered by the addition of onion powder. However, the expected production of LF by the fresh onion powder or enzyme solution was not detected by gas chromatography, possibly due to changes in the sample matrix. This method using fresh onion powder is an effective technique for preventing greening of fresh garlic that does not use artificial food additives or cause safety concerns.