楊靖鵬,范智義,樊明濤,宋云博,王　靜,魏新元

(西北農(nóng)林科技大學(xué)食品科學(xué)與工程學(xué)院,陜西楊凌 712100)

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富硒乳酸菌及其發(fā)酵食品的研究進(jìn)展

楊靖鵬,范智義,樊明濤,宋云博,王靜,魏新元*

(西北農(nóng)林科技大學(xué)食品科學(xué)與工程學(xué)院,陜西楊凌 712100)

乳酸菌作為益生菌中的一個類群,被廣泛應(yīng)用于食品、醫(yī)藥以及化妝品行業(yè)。硒,作為人體必需的微量元素之一,在人體新陳代謝及免疫調(diào)節(jié)方面起到至關(guān)重要的作用。近年來,富硒乳酸菌因?yàn)槠渫怀龅目寡趸?、抗炎癥、抗癌活性以及可以將無機(jī)硒轉(zhuǎn)化成有利于人體吸收的有機(jī)硒而備受關(guān)注。然而,乳酸菌對于硒的代謝途徑還有待進(jìn)一步深入研究;同時,對于富硒益生菌及其發(fā)酵食品的毒性及副作用也需要更為全面的測試與評估。本文從硒元素的價態(tài)、硒對于乳酸菌生長的影響、乳酸菌對硒的有機(jī)轉(zhuǎn)化、富硒乳酸菌的生物活性以及富硒功能食品這五個方面對其進(jìn)行綜述。

乳酸菌,硒,功能性食品

乳酸菌(Lacticacidbacteria,LAB)是世界一般公認(rèn)安全的食用細(xì)菌(General Regard As Safety,GRAS),常見的種屬包括乳球菌屬(Lactococcus)、腸球菌屬(Enterococcus)、酒球菌屬(Oenococcus)、片球菌屬(Pediococcus)、鏈球菌屬(Streptococcus)、乳桿菌屬(Lactobacillus)等[1-4]。乳酸菌因其突出的益生特性而被廣泛應(yīng)用于食品領(lǐng)域,用來發(fā)酵食品及飲料,包括乳制品(酸奶和奶酪)、發(fā)酵蔬菜(橄欖、醬菜以及泡菜)和發(fā)酵肉制品(臘腸)等。從不同環(huán)境發(fā)酵食品中分離出來的乳酸菌常常作為益生菌用于功能食品材料中[5]。

硒是人體所必需的一種微量元素,在人體新陳代謝、免疫調(diào)節(jié)等方面起到重要作用。與有機(jī)硒相比,無機(jī)硒因?yàn)槎拘源蠖y以被吸收利用。大量研究表明,通過微生物的生物轉(zhuǎn)化作用,可以將無機(jī)硒變?yōu)橛袡C(jī)態(tài)硒從而利于人體吸收并且相較于其他有機(jī)硒合成方式,既便宜又安全。目前,在富硒微生物的研究中,富硒酵母的研究最為廣泛[6]。而有研究表明,乳酸菌對于硒也具備富集和轉(zhuǎn)化的能力。

1　硒元素

1.1硒的重要作用

硒,作為一種人體必需的微量元素,其重要性已被廣泛認(rèn)可。人體推薦攝入量為55 μg/d,最大量不超過400 μg/d[7]。近些年來,硒因?yàn)槠渫怀龅目寡趸匦砸约翱拱┨匦远鹆藦V泛關(guān)注[8]。硒在人體內(nèi)的主要功能包括新陳代謝的調(diào)節(jié),免疫力的提高,生殖能力的增強(qiáng),以及顯著的防癌作用等[9];此外,硒在清除自由基,延緩衰老,重金屬離子的解毒以及抗地方性流行病等方面,效果也十分突出[10]。大量研究表明,硒所起到的作用與其化學(xué)形態(tài)密切相關(guān)[11],其常見價態(tài)如表1[12]。其中,零價態(tài)的納米硒(Nano-Se)因?yàn)橐子诒蝗梭w吸收毒性小且能夠發(fā)揮無機(jī)硒和有機(jī)硒所共有的功能性質(zhì),如抗腫瘤、抗氧化、增強(qiáng)機(jī)體免疫力等而成為目前的研究熱門[13]。

表1　硒的價態(tài)及其化合物

1.2硒的毒性及價態(tài)

超過一定限量的硒會引起中毒,硒中毒一般分為急性中毒和慢性中毒。典型的急性中毒,會在幾分鐘或幾小時內(nèi)就出現(xiàn)癥狀;慢性中毒則是因?yàn)榉磸?fù)攝入少量的硒積累所致,相應(yīng)癥狀會在幾天甚至更長時間后才出現(xiàn),有時因個體差異而有所不同[14],不同化學(xué)結(jié)構(gòu)的硒能夠產(chǎn)生不同的毒性。一般而言,無機(jī)硒的毒性比有機(jī)硒大,有機(jī)硒的毒性比膠體狀態(tài)單質(zhì)硒大,納米硒的毒性最小。Zhang等[15]對納米硒和亞硒酸鈉的極性毒性進(jìn)行比較,發(fā)現(xiàn)納米硒對于老鼠生長的抑制作用更小;同時,納米硒造成的肝功能異常程度更輕,其急性毒性是亞硒酸鈉的1/7。而大鼠口服實(shí)驗(yàn)中,亞硒酸鈉的平均致死量(LD50)為7 mg Se/kg,硫化硒的平均致死量為138 mg Se/kg,而單質(zhì)硒的平均致死量為6700 mg Se/kg[16]。

2　乳酸菌對硒的富集及生物轉(zhuǎn)化

微生物對于硒的有機(jī)轉(zhuǎn)化是當(dāng)前的研究熱門。Sarathchandra等[17]在進(jìn)行富硒巨大芽孢桿菌(Bacillusmegaterium)研究時,發(fā)現(xiàn)有紅色物質(zhì)的生成。此外,深紅紅螺菌(Rhodospirillumrubrum)、大腸桿菌(Escherichiacoli)、熒光假單胞菌(Pseudomonasfluorescens)、枯草芽孢桿菌(Bacillussubtilis)、酒色著色菌(Chromatiumvinosum)、脫硫桿菌(Desulfovibriodesulfuricans)、球形紅細(xì)菌(Rhodobactersphaeroides)等多種細(xì)菌也具有將硒酸鹽或亞硒酸鹽轉(zhuǎn)化為這種紅色物質(zhì)的能力[18-20]。此外,酵母、真菌、藻類及植物對硒的生物富集轉(zhuǎn)化實(shí)驗(yàn)中同樣觀察到了這種紅色物質(zhì)生成的現(xiàn)象;后續(xù)研究表明,這種紅色物質(zhì)主要成分為單質(zhì)硒。

乳酸菌具有抗菌、產(chǎn)多種維生素、胞外多糖等益生特性而被廣泛應(yīng)用于食品工業(yè)中。隨著研究深入,也發(fā)現(xiàn)乳酸菌具有對金屬離子吸附、攝入以及進(jìn)行生物轉(zhuǎn)換的特性[21]。1995年,Calomme[22]通過研究乳桿菌,發(fā)現(xiàn)其對于硒具有一定的富集作用,這是對乳酸菌具有富硒作用的第一次報(bào)道。保加利亞乳桿菌富硒示意圖(圖1)[23]如下。

圖1　乳桿菌富硒前后的對比,富硒前(A)富硒后(B)Fig.1　Comparison of lactobacillus before and afterthe Se-enrichment process,before(A)after(B)

乳酸菌對于不同價態(tài)的無機(jī)硒轉(zhuǎn)化效力及產(chǎn)生的有機(jī)硒形態(tài)也不同。與乳酸菌具有共性的動物雙歧桿菌可以將無機(jī)硒轉(zhuǎn)化為另一種重要的有機(jī)硒化合物——硒代蛋氨酸[24]。向酸奶中加入亞硒酸鈉,乳酸菌可以將其轉(zhuǎn)化為硒代胱氨酸和甲基硒代半胱氨酸,但硒酸鈉不能被轉(zhuǎn)化成同樣的產(chǎn)物[25]。在無機(jī)硒溶液中,通過生物轉(zhuǎn)化作用,乳酸菌可以將無機(jī)態(tài)的硒轉(zhuǎn)換成不同形態(tài)的有機(jī)硒,而這些有機(jī)態(tài)硒主要是硒代胱氨酸、硒代蛋氨酸、硒代半胱氨酸、富硒生物質(zhì)、二甲基硒、二甲基二硒以及單質(zhì)硒等。其中,硒代半胱氨酸是轉(zhuǎn)化后的主要產(chǎn)物,它能夠進(jìn)一步被合成硒蛋白。

表2　乳酸菌對硒的生物轉(zhuǎn)化

同樣具有富硒能力的乳酸菌還有植物乳桿菌(Lactobacillusplantarum)、保加利亞乳桿菌(Lactobacillusbulgaricus)、干酪乳桿菌(Lactobacilluscasei)、鼠李糖乳桿菌(Lactobacillusrhamnosus)、發(fā)酵乳桿菌(Lactobacillusfermentum)、羅伊氏乳桿菌(Lactobacillusreuteri)、短乳桿菌(Lactobacillusbrevis)、舊金山乳桿菌(Lactobacillussanfranciscensis)以及布氏乳桿菌(Lactobacillusbuchneri)等[26-27]。研究表明,絕大多數(shù)乳酸菌具有富集硒并能將無機(jī)硒轉(zhuǎn)化為有機(jī)硒的能力;由表2可以看出,大多數(shù)乳酸菌能夠?qū)?4價的無機(jī)硒轉(zhuǎn)化為單質(zhì)硒以及有機(jī)態(tài)硒[28]。

3　硒對于乳酸菌生長的影響

Xia[23]等在實(shí)驗(yàn)中發(fā)現(xiàn)保加利亞乳桿菌在一定質(zhì)量濃度的亞硒酸鈉溶液中可以富集大量的硒,且菌體本身能很好的生長;在終濃度為1～16 mg/L含有亞硒酸鈉的培養(yǎng)液中,保加利亞乳桿菌的富硒效果很好,其最高富硒量達(dá)到了12.45± 1.04 mg/L;此外,通過調(diào)整必需元素的比例(如磷、鎂、錳、鋅、鈣及總氨基酸)從而提高有機(jī)體的營養(yǎng)價值及生物作用,同時產(chǎn)生大量不溶于水的單質(zhì)硒。曾議霆[36]在培養(yǎng)液中加入6 μg/mL的亞硒酸鈉溶液,培養(yǎng)一段時間后,比較加硒和未加硒乳酸菌生物量的變化,發(fā)現(xiàn)加硒后的植物乳桿菌BC-25的生物量較多,達(dá)到了0.2572 g/100 mL(對照組為0.2472 g/100 mL),這說明一定濃度的硒溶液不僅不會對菌株產(chǎn)生負(fù)面影響,甚至還會促進(jìn)其生長發(fā)育。然而,濃度超過6 μg/mL的硒溶液卻對植物乳桿菌M產(chǎn)生了副作用,黃秀錦[37]發(fā)現(xiàn)保加利亞乳桿菌在富硒過程中,其生物量隨亞硒酸鈉濃度的增加呈下降趨勢,而富硒量則呈上升趨勢,在亞硒酸鈉濃度超過14 μg/mL后,生物量從0.48 g/100 mL急劇下降到近0.40 g/100 mL,乳酸菌對硒的富集由原來的生理性富集轉(zhuǎn)變?yōu)椴±硇愿患?。因?對于富硒乳酸菌的篩選和馴化,硒溶液的濃度是一個重要的影響因素,大量實(shí)驗(yàn)表明少量的硒可以促進(jìn)菌株的生長。而一些特殊菌種,如耐久腸球菌具有在硒濃度很高的培養(yǎng)基中生長并富集硒的能力[38]。富集的硒一部分用于硒代胱氨酸的合成,而另一部分可以被還原成零價態(tài)的單質(zhì)硒,單質(zhì)硒在溶液中呈現(xiàn)紅色[23]。

4　富硒乳酸菌生物活性研究

4.1富硒乳酸菌抗菌活性

某些含硒化合物在不同的濃度范圍內(nèi)具有抗菌活性[39]。大腸桿菌產(chǎn)生的腸毒素能夠引起人或動物的腹瀉[40],而抗生素對于這類疾病的治療并不明顯,甚至有證據(jù)表明某些抗生素的使用會引起腎臟并發(fā)癥[41]。益生菌因?yàn)槠渚哂卸喾N益生效果包括平衡腸道菌群,被認(rèn)為是可行的替代方法[42]。乳酸菌在抑制某些致病菌方面尤為突出[43],Yang等通過動物實(shí)驗(yàn)發(fā)現(xiàn),攝入了富硒嗜酸乳桿菌的小鼠,由致病性大腸桿菌所引起的死亡率相比于對照組(50.00%)、益生菌攝入組(43.75%)、亞硒酸鈉攝入組(43.36%)、有機(jī)硒復(fù)合益生元攝入組(25.00%)、氧四環(huán)素?cái)z入組(25.10%)是最低的,為18.75%。在體內(nèi)以及體外實(shí)驗(yàn)中,富硒乳酸菌對于致病性大腸桿菌都表現(xiàn)出極強(qiáng)的抗性[44]。6×109CFU的屎腸球菌與55 g有機(jī)硒混合,制成的膠囊能夠減少炎癥性腸病中致病菌的數(shù)量,并降低結(jié)腸癌的發(fā)病率[45]。而最近的研究表明,富硒乳酸菌還能夠?qū)δ承┱婢鸬揭种谱饔?Kheradmand[46]等在實(shí)驗(yàn)中將二氧化硒馴化后的益生菌作用于白色念珠菌,發(fā)現(xiàn)其抗真菌作用突出。

4.2富硒乳酸菌抗氧化活性

硒具有抗氧化特性。大量研究表明,不同膳食結(jié)構(gòu)中的硒都能夠提高人體組織的抗氧化能力。而這種功能特性主要是由于人體中的硒蛋白,如谷光氨肽過氧化物酶、硫氧還蛋白還原酶、脫碘酶以及硒蛋白P(硒蛋白的一種)的活性被顯著提高而引起[47]。Penas[33]等在制作德國泡菜時,于發(fā)酵前加入0.3 mg亞硒酸鈉,發(fā)酵后發(fā)現(xiàn)泡菜抗氧化活性因?yàn)橛袡C(jī)硒的生成而顯著提高,為對照組的1.75倍。Chen[48]等在動物實(shí)驗(yàn)中發(fā)現(xiàn),口服富硒乳酸桿菌可以提高抗氧化酶活性,如超氧化物歧化酶等,而這一作用機(jī)制對于實(shí)驗(yàn)中人為造成的小鼠肝損傷具有抑制作用。而在Ren[49]等的實(shí)驗(yàn)中發(fā)現(xiàn),動物體內(nèi)這類酶的活性以及總體抗氧化能力在攝入了富硒富鋅益生菌后也有顯著提高。此外,從乳酸乳球菌乳酸亞種中分離得到的胞外多糖,在富硒后,能夠使血清和肝臟中的谷胱甘肽過氧化物酶活性提高,從而提高了整體抗氧化活性和免疫調(diào)節(jié)能力[50];同時,這類富硒多糖可以對糖尿病起到一定的抑制作用[51]。

表3　富硒益生菌及發(fā)酵食品的健康功效

4.3富硒乳酸菌抗癌活性

化合價不同的硒均具有不同的抗突變和抗癌作用[52]。濃度合適的硒溶液可以有效降低癌癥發(fā)病率,但濃度過高就可能引起中毒。糞腸球菌-74在一定濃度硒的刺激下,其抗氧氟沙星能力顯著提高[53]。雖然硒誘導(dǎo)益生菌抗突變的機(jī)制還沒有被完全闡明,但在生物轉(zhuǎn)化的過程中,不同種類有機(jī)硒的產(chǎn)生成為引發(fā)這種機(jī)制的最大可能。在癌癥基因治療方面,某些細(xì)菌能夠作用于實(shí)體瘤并釋放治療性分子[54]。Xu[55]等在實(shí)驗(yàn)中發(fā)現(xiàn),與乳酸菌類似的雙歧桿菌可以在實(shí)體瘤中生長和擴(kuò)增,并將抗癌基因轉(zhuǎn)入腫瘤中。富硒長雙歧桿菌細(xì)胞能夠結(jié)合重組內(nèi)皮抑素和白介素2基因,對于H22腫瘤表現(xiàn)出抗癌效果[56]。此外,包含了納米硒的植物乳桿菌[57]以及短乳桿菌細(xì)胞[58]也可以通過刺激作用,增加小鼠體內(nèi)促炎癥細(xì)胞因子的產(chǎn)量,從而使癌癥預(yù)報(bào)過程中的免疫反應(yīng)得到提高。

5　富硒乳酸菌及其發(fā)酵食品

硒對于人體的健康起到重要作用;因此,富硒發(fā)酵食品以及相關(guān)益生菌的研發(fā)對于人體營養(yǎng)需求也是十分必要的。在飲食中添加硒,尤其是富硒食品[59]以及硒的膳食補(bǔ)充劑[60]這一方法已經(jīng)受到廣泛重視與認(rèn)可。目前,已報(bào)道過具有促進(jìn)人體健康功效的富硒發(fā)酵食品如表3所示。由微生物發(fā)酵制成的富硒食品,能夠?yàn)槿梭w提供所需的硒代半胱氨酸以及硒蛋白等有機(jī)態(tài)硒,而這種由微生物轉(zhuǎn)化出的硒,更為安全也更為營養(yǎng);因此,食用含有富硒微生物的發(fā)酵食品,可以達(dá)到補(bǔ)充人體所需硒元素的目的,表3中給出了已報(bào)道過的富硒食品[61]。

Palomo[67]等對富硒酸奶進(jìn)行分析,發(fā)現(xiàn)硒對于乳酸桿菌中伴侶蛋白的表達(dá)起到了重要作用,同時也減少了奶中的應(yīng)激因子對于乳酸桿菌的不利影響。此外,通過對氨基酸成分進(jìn)行分析,發(fā)現(xiàn)硒代半胱氨酸是最主要的含硒種類。而在肽譜圖中,含硒氨基酸片段分析也證實(shí)了硒在硫氧還蛋白、谷氧還蛋白、清蛋白、β-乳球蛋白以及乳過氧化物酶的存在。Deng[68]等從西藏靈菇中分離出了耐硒能力極強(qiáng)的短乳桿菌CGMCC No. 6683,富硒培養(yǎng)后,與嗜熱鏈球菌、保加利亞乳桿菌混合用來發(fā)酵脫脂乳,結(jié)果表明酸奶中硒含量顯著提高,為24 μg/g;同時,也檢測到了含量較高的單質(zhì)硒。

綠茶中含有豐富的必需膳食營養(yǎng)素和抗氧化劑[69]。Molan[70]等在研究中發(fā)現(xiàn),富硒綠茶能夠促進(jìn)乳酸桿菌和雙歧桿菌的生長。Vodnar[71]等對富硒綠茶進(jìn)行研究,在體外實(shí)驗(yàn)中,發(fā)現(xiàn)85.8～96 mg/kg的富硒綠茶在不同濃度的殼聚糖海藻酸液中,對干酪乳桿菌和植物乳桿菌起到了保護(hù)作用。將2 g富硒綠茶溶于100 mL殼聚糖中,做成微型膠囊,在維持菌株穩(wěn)定性上更加有效;同時,在4 ℃下儲藏30 d,菌株活性也明顯提高;在腸道模擬實(shí)驗(yàn)中,富硒綠茶也顯著提高了乳酸菌的存活率,使其活菌數(shù)達(dá)到了109CFU以上的益生水平。目前,富硒乳酸菌及其發(fā)酵食品因?yàn)橥怀龅膬?yōu)良特性,已經(jīng)引起了廣泛關(guān)注。

6　總結(jié)

繼富硒酵母之后,富硒乳酸菌也倍受關(guān)注。大量的實(shí)驗(yàn)結(jié)果表明,乳酸菌能夠富集硒并通過生物轉(zhuǎn)化作用使其成為有機(jī)態(tài)硒,從而更利于人體吸收。而這種富硒菌使得種類豐富的富硒型功能食品的出現(xiàn)成為可能,同時為解決地方性硒攝入量不足問題提供了新方案。通過生物轉(zhuǎn)換作用,乳酸菌可以將無機(jī)硒轉(zhuǎn)化為硒代胱氨酸、硒代蛋氨酸、硒甲基硒代半胱氨酸、二甲基硒、二甲基二硒以及單質(zhì)硒等。對于乳酸菌自身而言,其某些生理特性,如生長狀態(tài)、蛋白表達(dá)方式、抗氧化活性、礦物質(zhì)及氨基酸的成分組成也會受到影響，進(jìn)入到乳酸菌細(xì)胞內(nèi)的硒元素,對于相關(guān)酶的活性有一定的刺激作用,這也是富硒乳酸菌生物活性相較于普通菌突出的原因之一。

近些年來,富硒益生菌及其發(fā)酵食品因?yàn)榫哂卸喾N健康功效而受到了廣泛的認(rèn)可,這些功效包括生物利用率和抗氧化性能的提高,抗菌、抗癌、抗突變能力的加強(qiáng)等。一些臨床實(shí)驗(yàn)也證實(shí),某些富硒乳酸菌所轉(zhuǎn)化出的單質(zhì)硒或純種硒化合物具有增強(qiáng)免疫刺激、抗衰老以及減少妊娠并發(fā)癥的作用。富硒型益生菌產(chǎn)品在營養(yǎng)基因組學(xué)上的應(yīng)用,正在為人類的健康帶來福音。

然而,腸道微生物如何對硒進(jìn)行代謝以及某些臨床表現(xiàn)出現(xiàn)的原因有待進(jìn)一步深入。同時,對于富硒益生菌及其功能產(chǎn)品的毒性及副作用也需要更為全面的測試。因此,在這類功能食品成為大眾消費(fèi)品之前,更為廣泛以及更加深入的調(diào)查和研究是十分必要的。而對于不同種屬的乳酸菌,其對于硒的代謝途徑及相關(guān)代謝模型也有待進(jìn)一步確定。

[1]Limsowtin G K Y,Broome M C,Powell I B. Lactic acid bacteria,taxonomy[J]. Encyclopedia of Dairy Sciences,2002:1470-1478.

[2]Makarova K,Slesarev A,Wolf Y,et al. Comparative genomics of the lactic acid bacteria[J]. Proceedings of the National Academy of Sciences,2006,103(42):15611-15616.

[3]Stiles M E,Holzapfel W H. Lactic acid bacteria of foods and their current taxonomy[J]. International Journal of Food Microbiology,1997,36(1):1-29.

[4]Pot B,Ludwig W,Kersters K,et al. Taxonomy of lactic acid bacteria[M]//Bacteriocins of lactic acid bacteria. Springer US,1994:13-90.

[5]Solieri L,Bianchi A,Mottolese G,et al. Tailoring the probiotic potential of non-starter Lactobacillus strains from ripened Parmigiano Reggiano cheese byinvitroscreening and principal component analysis[J]. Food Microbiology,2014(38):240-249.

[6]Dumont E,Vanhaecke F,Cornelis R. Selenium speciation from food source to metabolites:a critical review[J]. Analytical and Bioanalytical Chemistry,2006,385(7):1304-1323.

[7]Food and Nutrition Board Staff,Panel on Dietary Antioxidants,Institute of Medicine Staff. Dietary Reference Intakes for Vitamin C,Vitamin E,Selenium and Carotenoids:A Report of the Panel on Dietary Antioxidants and Related Compounds,Subcommittees on Upper Reference Levels of Nutrients and of Interpretation and Use of Dietary Reference Intakes and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes,Food and Nutrition Board,Institute of Medicine[M]. National Academies Press,2000.

[8]Combs G F. Current evidence and research needs to support a health claim for selenium and cancer prevention[J]. The Journal of Nutrition,2005,135(2):343-347.

[9]Mater D D G,Bretigny L,Firmesse O,et al. Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus survive gastrointestinal transit of healthy volunteers consuming yogurt[J]. FEMS Microbiology Letters,2005,250(2):185-187.

[10]Navarro-Alarcon M,Lopez-Martnez M C. Essentiality of selenium in the human body:relationship with different diseases[J]. Science of the Total Environment,2000,249(1):347-371.

[11]Zhu Z,Jiang W,Ganther H E,et al. Activity of Se-allylselenocysteine in the presence of methionine γ-lyase on cell growth,DNA integrity,apoptosis,and cell-cycle regulatory molecules[J]. Molecular carcinogenesis,2000,29(4):191-197.

[12]Nuttall K L. Evaluating selenium poisoning[J]. Annals of Clinical & Laboratory Science,2006,36(4):409-420.

[13]鄧修元. 納米硒的臨床研究進(jìn)展[J]. 國際檢驗(yàn)醫(yī)學(xué)雜志,2013,34(2):178-180.

[14]Whanger P,Vendeland S,Park Y C,et al. Metabolism of subtoxic levels of selenium in animals and humans[J]. Annals of Clinical & Laboratory Science,1996,26(2):99-113.

[15]Zhang J,Wang H,Yan X,et al. Comparison of short-term toxicity between Nano-Se and selenite in mice[J]. Life Sciences,2005,76(10):1099-1109.

[16]Cummins L M,Kimura E T. Safety evaluation of selenium sulfide antidandruff shampoos[J]. Toxicology and Applied Pharmacology,1971,20(1):89-96.

[17]Sarathchandra S U,Watkinson J H. Oxidation of elemental selenium to selenite by Bacillus megaterium[J]. Science,1981,211(4482):600-601.

[18]Kessi J,Hanselmann K W. Similarities between the abiotic reduction of selenite with glutathione and the dissimilatory reaction mediated by Rhodospirillum rubrum and Escherichia coli[J]. Journal of Biological Chemistry,2004,279(49):50662-50669.

[19]Nelson D C,Casey W H,Sison J D,et al. Selenium uptake by sulfur-accumulating bacteria[J]. Geochimica et Cosmochimica Acta,1996,60(18):3531-3539.

[20]Garbisu C,Ishii T,Leighton T,et al. Bacterial reduction of selenite to elemental selenium[J]. Chemical Geology,1996,132(1):199-204.

[22]Calomme M R,Branden K,Berghe D A. Selenium and Lactobacillus species[J]. Journal of Applied Bacteriology,1995,79(3):331-340.

[23]Xia S K,Chen L,Liang J Q. Enriched selenium and its effects on growth and biochemical composition in Lactobacillus bulgaricus[J]. Journal of Agricultural and Food Chemistry,2007,55(6):2413-2417.

[24]Zhang B,Zhou K,Zhang J,et al. Accumulation and species distribution of selenium in Se-enriched bacterial cells of the Bifidobacterium animalis 01[J]. Food Chemistry,2009,115(2):727-734.

[25]Alzate A,Caas B,Pérez-Munguía S,et al. Evaluation of the inorganic selenium biotransformation in selenium-enriched yogurt by HPLC-ICP-MS[J]. Journal of Agricultural and Food Chemistry,2007,55(24):9776-9783.

[26]Galano E,Mangiapane E,Bianga J,et al. Privileged incorporation of selenium as selenocysteine in Lactobacillus reuteri proteins demonstrated by selenium-specific imaging and proteomics[J]. Molecular & Cellular Proteomics,2013,12(8):2196-2204.

[27]Mogna L,Nicola S,Pane M,et al. Selenium and zinc internalized by Lactobacillus buchneri Lb26(DSM 16341)and Bifidobacterium lactis Bb1(DSM 17850):improved bioavailability using a new biological approach[J]. Journal of clinical gastroenterology,2012,46:S41-S45.

[28]Pophaly S D,Singh P,Kumar H,et al. Selenium enrichment of lactic acid bacteria and bifidobacteria:a functional food perspective[J]. Trends in Food Science & Technology,2014,39(2):135-145.

[29]Calomme M R,Branden K,Berghe D A. Selenium and Lactobacillus species[J]. Journal of Applied Bacteriology,1995,79(3):331-340.

[30]Andreoni V,Luischi M M,Cavalca L,et al. Selenite tolerance and accumulation in the Lactobacillus species[J]. Annals of Microbiology,2000,50(1):77-88.

[31]Pieniz S,Okeke B C,Andreazza R,et al. Evaluation of selenite bioremoval from liquid culture by Enterococcus species[J]. Microbiological research,2011,166(3):176-185.

[32]Lamberti C,Mangiapane E,Pessione A,et al. Proteomic characterization of a selenium-metabolizing probiotic Lactobacillus reuteri Lb2 BM for nutraceutical applications[J]. Proteomics,2011,11(11):2212-2221.

[34]Krittaphol W,McDowell A,Thomson C D,et al. Biotransformation of L-selenomethionine and selenite in rat gut contents[J]. Biological trace element research,2011,139(2):188-196.

[35]Eszenyi P,Sztrik A,Babka B,et al. Production of Lactomicrosel? and nanosize(100-500 nm)selenium spheres by probiotic lactic acid bacteria[C]//Int. Conf. Food Eng. Biotechnol,2011(9):97-101.

[36]曾議霆,郭溪浪,周康,等. 富硒乳酸菌的篩選及鑒定[J].食品科學(xué),2015(3):34.

[37]黃秀錦. 富硒乳酸菌發(fā)酵條件的研究[J]. 中國調(diào)味品,2009(12):54-60.

[38]Pieniz S,Andreazza R,Anghinoni T,et al. Probiotic potential,antimicrobial and antioxidant activities of Enterococcus durans strain LAB18s[J]. Food Control,2014(37):251-256.

[39]Xi L,Yi L,Jun W,et al. Microcalorimetric study of Staphylococcus aureus growth affected by selenium compounds[J].Thermochimica acta,2002,387(1):57-61.

[40]Edelman S,Leskel? S,Ron E,et al.Invitroadhesion of an avian pathogenic Escherichia coli O78 strain to surfaces of the chicken intestinal tract and to ileal mucus[J]. Veterinary microbiology,2003,91(1):41-56.

[41]M?lbak K,Mead P S,Griffin P M. Antimicrobial therapy in patients with Escherichia coli O157∶H7 infection[J]. JAMA,2002,288(8):1014-1016.

[42]De Vries M C,Vaughan E E,Kleerebezem M,et al. Lactobacillus plantarum-survival,functional and potential probiotic properties in the human intestinal tract[J]. International Dairy Journal,2006,16(9):1018-1028.

[43]Reid G,Burton J. Use of Lactobacillus to prevent infection by pathogenic bacteria[J]. Microbes and Infection,2002,4(3):319-324.

[44]Yang J,Huang K,Qin S,et al. Antibacterial action of selenium-enriched probiotics against pathogenic Escherichia coli[J]. Digestive diseases and sciences,2009,54(2):246-254.

[46]Kheradmand E,Rafii F,Yazdi M H,et al. The antimicrobial effects of selenium nanoparticle-enriched probiotics and their fermented broth against Candida albicans[J]. DARU Journal of Pharmaceutical Sciences,2014,22(1):48.

[47]Rayman M P. The importance of selenium to human health[J]. The lancet,2000,356(9225):233-241.

[48]Chen L,Pan D D,Zhou J,et al. Protective effect of selenium-enriched lactobacillus on CCl～4-induced liver injury in mice and its possible mechanisms[J]. World Journal of Gastroenterology,2005,11(37):5795.

[49]Ren Z,Zhao Z,Wang Y,et al. Preparation of selenium/zinc-enriched probiotics and their effect on blood selenium and zinc concentrations,antioxidant capacities,and intestinal microflora in canine[J]. Biological trace element research,2011,141(1-3):170-183.

[50]Guo Y,Pan D,Li H,et al. Antioxidant and immunomodulatory activity of selenium exopolysaccharide produced by Lactococcus lactis subsp. lactis[J]. Food chemistry,2013,138(1):84-89.

[51]Zhou X,Wang F,Yang H,et al. Seleniumenriched exopolysaccharides produced by Enterobacter cloacae Z0206 alleviate adipose inflammation in diabetic KKAy mice through the AMPK/SirT1 pathway[J]. Molecular medicine reports,2014,9(2):683-688.

[52]Kim Y S,Milner J. Molecular targets for selenium in cancer prevention[J]. Nutrition and cancer,2001,40(1):50-54.

[53]Kri?kova L,Belicova A,Dobias J,et al. Selenium enhances the antimutagenic activity of probiotic bacterium Enterococcus faecium M-74[J]. World Journal of Microbiology and Biotechnology,2002,18(9):867-873.

[54]Gardlik R,Behuliak M,Palffy R,et al. Gene therapy for cancer:bacteria-mediated anti-angiogenesis therapy[J]. Gene therapy,2011,18(5):425-431.

[55]Xu Y F,Zhu L P,Hu B,et al. A new expression plasmid in Bifidobacterium longum as a delivery system of endostatin for cancer gene therapy[J]. Cancer gene therapy,2007,14(2):151-157.

[56]Yin Y,Wang Q X,Chen X,et al. Antitumor efficacy of Bifidobacterium longum carrying endostatin gene enriched with selenium and the distribution of selenium[J]. African Journal of Microbiology Research,2011,5(31):5615-5621.

[57]Yazdi M H,Mahdavi M,Kheradmand E,et al. The preventive oral supplementation of a selenium nanoparticle-enriched probiotic increases the immune response and lifespan of 4T1 breast cancer bearing mice[J]. Arzneimittelforschung,2012,62(11):525.

[58]Yazdi M H,Mahdavi M,Setayesh N,et al. Selenium nanoparticle-enriched Lactobacillus brevis causes more efficient immune responsesinvivoand reduces the liver metastasis in metastatic form of mouse breast cancer[J]. Daru,2013,21(1):33.

[59]Sánchez-Martínez M,da Silva E G P,Pérez-Corona T,et al. Selenite biotransformation during brewing. Evaluation by HPLC-ICP-MS[J]. Talanta,2012(88):272-276.

[60]Zembrzuska J,Matusiewicz H,Polkowska-Motrenko H,et al. Simultaneous quantitation and identification of organic and inorganic selenium in diet supplements by liquid chromatography with tandem mass spectrometry[J]. Food chemistry,2014(142):178-187.

[61]Alzate A,Pérez-Conde M C,Gutiérrez A M,et al. Selenium-enriched fermented milk:a suitable dairy product to improve selenium intake in humans[J]. International Dairy Journal,2010,20(11):761-769.

[62]Achanta K,Aryana K J,Boeneke C A. Fat free plain set yogurts fortified with various minerals[J]. LWT-Food Science and Technology,2007,40(3):424-429.

[63]Belicová A,Kri?ková L,Dobias J,et al. Synergic activity of selenium and probiotic bacteriumEnterococcus faecium M-74 against selected mutagens inSalmonella assay[J]. Folia microbiologica,2004,49(3):301-305.

[64]Wang Q X,Wang J J,Xu G X. Therapeutic efficacy of Bifidobacterium longum carrying Interleukin-2 gene enriched with selenium in mice transplanted H 22 liver tumor[J]. Chinese Journal of Microecology,2011,23(9).

[65]Ibrahim H A M,Zhu Y,Wu C,et al. Selenium-enriched probiotics improves murine male fertility compromised by high fat diet[J]. Biological Trace Element Research,2012,147(1-3):251-260.

[66]Hlivak P,Odraska J,Ferencik M,et al. One-year application of probiotic strain Enterococcus faecium M-74 decreases serum cholesterol levels[J]. Bratisl Lek Listy,2005,106(2):67-72.

[67]Palomo M,Gutiérrez A M,Pérez-Conde M C,et al. Se metallomics during lactic fermentation of Se-enriched yogurt[J]. Food Chemistry,2014(164):371-379.

[68]Deng Y,Man C,Fan Y,et al. Preparation of elemental selenium-enriched fermented milk by newly isolated Lactobacillus brevis from kefir grains[J]. International Dairy Journal,2015(44):31-36.

[69]Costa A S G,Nunes M A,Almeida I M C,et al. Teas,dietary supplements and fruit juices:A comparative study regarding antioxidant activity and bioactive compounds[J]. LWT-Food Science and Technology,2012,49(2):324-328.

[70]Molan A L,Flanagan J,Wei W,et al. Selenium-containing green tea has higher antioxidant and prebiotic activities than regular green tea[J]. Food Chemistry,2009,114(3):829-835.

[71]Vodnar D C,Socaciu C. Selenium enriched green tea increase stability of Lactobacillus casei and Lactobacillus plantarum in chitosan coated alginate microcapsules during exposure to simulated gastrointestinal and refrigerated conditions[J]. LWT-Food Science and Technology,2014,57(1):406-411.

Research advance of Se-enriched lactic acid bacteria and relevant fermented foods

YANG Jing-peng,FAN Zhi-yi,FAN Ming-tao,SONG Yun-bo,WANG Jing,WEI Xin-yuan*

(College of Food Science and Engineering,Northwest A&F University,Yangling 712100,China)

Lactic acid bacteria are a class of probiotics widely used in food,medical and cosmetics industry. As an essential trace element for human,selenium(Se)plays a critical role in metabolism and immunoregulation. In recent decades,Se-enriched lactic acid bacteria attract extensive attention due to their outstanding antioxidant,anti-inflammatory,antitumor activities and the ability to transform inorganic selenium into organic form,which is beneficial to human absorption. However,further studies about metabolic pathways of Se by LAB are needed;meanwhile,it is necessary to test and evaluate the toxicities and side effects of Se-enriched probiotics and their fermented foods. In this paper,the oxidation state of selenium,the effects on the growth of LAB by selenium,the transformation of organic selenium by LAB,bioactivities of Se-enriched LAB and Se-enriched functional foods were summarized.

lactic acid bacteria;Selenium;functional food

2015-11-19

楊靖鵬(1990-)，男，碩士研究生，研究方向：食品高新技術(shù)，E-mail：xhwy008@gmail.com。

魏新元(1971-)，男，博士，副教授，研究方向：食品高新技術(shù)，E-mail：wheixinyuan@126.com。

西北農(nóng)林科技大學(xué)基本科研業(yè)務(wù)費(fèi)專項(xiàng)(QN2011138)。

TS201.3

A

1002-0306(2016)11-0355-07

10.13386/j.issn1002-0306.2016.11.065