为什么纳豆有黏稠的拉丝？
Why does natto have sticky threads?
纳豆菌（枯草芽孢杆菌）发酵大豆时分泌γ-多聚谷氨酸等胞外多糖，这些大分子溶于水形成黏稠拉丝。这种黏丝有助肠道健康和挂味，是纳豆的特征。发酵温度和湿度决定黏性强弱。
During fermentation, Bacillus subtilis secretes extracellular polysaccharides such as gamma-polyglutamic acid, and these large molecules dissolve to form the sticky strings. The slime aids gut health and carries flavor, defining natto's character. Temperature and humidity set how stringy it gets.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#纳豆 #多糖 #发酵
为什么有些奶酪（如瑞士奶酪）有大小不一的孔洞？
Why do some cheeses like Swiss have holes?
某些丙酸菌在成熟时分解乳酸产生二氧化碳，气体在半固体凝乳中聚集成孔，形成眼睛。孔洞大小和数量取决于菌种、温度和凝乳硬度。孔太多反而可能说明发酵过度。
Certain propionic bacteria break down lactate during ripening and release carbon dioxide, which gathers into bubbles in the semi-solid curd to form eyes. Hole size and number depend on the strain, temperature, and curd firmness. Too many holes can signal over-fermentation.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#奶酪 #丙酸菌 #孔洞
为什么酱油、面酱要长时间发酵才香？
Why do soy sauce and bean paste need long fermentation to smell good?
制酱时米曲霉等先把大豆、小麦的蛋白质和淀粉分解成氨基酸和糖，再经长期发酵产生美拉德反应和众多风味物。时间越长，鲜味（谷氨酸）和酱香越浓。这是酿造酱油比化学勾兑更香的原因。
In brewing, Aspergillus oryzae first breaks soy and wheat proteins and starch into amino acids and sugars, then long fermentation drives Maillard reactions and many flavor compounds. The longer it ages, the richer the umami (glutamate) and savory aroma. That is why brewed sauce beats chemically blended ones.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#酱油 #酿造 #鲜味
为什么康普茶（红茶菌）有酸甜味和微量酒精？
Why does kombucha taste sweet-sour with a trace of alcohol?
康普茶靠红茶菌（酵母和醋酸菌共生）发酵，酵母产少量酒精、醋酸菌把酒精氧化成醋酸，所以又酸又带微醇。糖被消耗后口感变酸，气泡来自发酵产气。它含糖量仍不低，不宜当水喝。
Kombucha ferments with a SCOBY—yeast and acetic-acid bacteria together—where yeast makes a little alcohol and the bacteria oxidize it to acetic acid, giving sourness plus a faint bite. As sugar is consumed it turns more acidic, and bubbles come from fermentation gas. It is still sugary and not a water substitute.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#康普茶 #共生发酵 #醋酸
为什么长时间发酵的酱类（酱油、豆酱）会变鲜（umami）？这和蛋白酶有什么关系？
Why do long-fermented sauces like soy sauce and bean paste become savory (umami), and what role do proteases play?
米曲霉等霉菌分泌蛋白酶，把大豆蛋白逐步水解成肽和游离氨基酸，其中谷氨酸是鲜味的主要来源。同时淀粉酶把淀粉变成糖，微生物代谢产生醇、酸、酯，共同形成酱油"鲜中带香"的复杂风味。
Molds such as Aspergillus oryzae secrete proteases that stepwise hydrolyze soy protein into peptides and free amino acids, among which glutamate is the main source of umami. Amylases convert starch to sugars, and microbial metabolism yields alcohols, acids, and esters that together build soy sauce's savory, aromatic profile.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
GB/T 18186《酿造酱油》国家标准；McGee《食物与烹饪》（On Food and Cooking 修订版），发酵章节
GB/T 18186 (Chinese national standard for brewed soy sauce); H. McGee, "On Food and Cooking" (rev. ed.), Ch. Fermentation
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL4110479W：On food and cooking（首版
#鲜味 #谷氨酸 #蛋白酶 #米曲霉
为什么酒酿（醪糟）先甜后带酒味？
Why does fermented rice (jiuniang) taste sweet first and then alcoholic?
酒曲里的根霉等微生物先把糯米淀粉分解成葡萄糖，所以初期很甜。随后酵母菌把糖转化成酒精和二氧化碳，甜味渐减、酒味渐浓。发酵时间和温度控制着甜与酒的平衡。
Microbes like Rhizopus in the starter first break rice starch into glucose, so it is very sweet early on. Then yeast converts the sugar into alcohol and carbon dioxide, reducing sweetness and raising the alcoholic note. Time and temperature control the sweet-alcohol balance.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#酒酿 #糖化 #酒精发酵
从生化角度看，酒精发酵和乳酸发酵的根本区别是什么？
At the biochemical level, what is the fundamental difference between alcoholic and lactic-acid fermentation?
两者都发生在无氧条件下、以糖酵解产生的丙酮酸为底物。酒精发酵把丙酮酸脱羧成乙醛再还原为乙醇（并放出 CO₂）；乳酸发酵则直接把丙酮酸还原为乳酸，不产气。产物不同，决定了一种会冒泡、一种只变酸。
Both occur anaerobically on pyruvate from glycolysis. Alcoholic fermentation decarboxylates pyruvate to acetaldehyde and reduces it to ethanol (releasing CO₂); lactic-acid fermentation reduces pyruvate straight to lactate with no gas. The different products explain why one bubbles and the other merely sours.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Lehninger《生物化学原理》（第7版），第16章糖酵解与发酵
Lehninger, "Principles of Biochemistry" (7th ed.), Ch.16
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#酒精发酵 #乳酸发酵 #丙酮酸 #无氧代谢
为什么面团放冰箱低温慢发酵更好吃？
Why does cold, slow dough fermentation taste better?
低温让酵母活动变慢，延长发酵时间，使风味物质（有机酸、酯类）更充分生成，面香更浓。同时面筋松弛、延展性更好，成品组织细腻。这就是冷藏发酵（cold retard）受面包师欢迎的原因。
Low temperature slows the yeast, lengthening fermentation so flavor compounds like organic acids and esters develop more fully and the crumb smells richer. The gluten also relaxes and extends better for a finer texture. That is why bakers love cold retardation.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#冷藏发酵 #风味 #面筋
为什么做馒头包子要先把面团发起来？
Why must dough be proofed before making steamed buns?
酵母吃面团里的糖，呼吸产生二氧化碳气体，被面筋网络包住形成许多小气孔，面团就膨胀变松。蒸的时候气体受热膨胀、蛋白质凝固，成品蓬松多孔。这就是生物发酵膨松的原理。
Yeast eats the sugar in dough and respires, producing carbon dioxide trapped by the gluten network as tiny pockets, so the dough rises and loosens. During steaming the gas expands and the protein sets, leaving a fluffy, porous crumb. This is biological leavening.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#发面 #酵母 #二氧化碳
为什么啤酒、香槟有气泡？
Why do beer and champagne have bubbles?
发酵或人工充入的二氧化碳溶解在酒里，开瓶后压力下降，二氧化碳以气泡形式逸出。酵母发酵天然产气，所以啤酒、香槟有杀口感。温度低时溶解得更多，所以冰镇后气泡更细腻。
Carbon dioxide from fermentation or added mechanically dissolves in the drink, and on opening the pressure drops so CO2 escapes as bubbles. Yeast naturally produces the gas, giving beer and champagne their fizz. Cold liquid holds more, so chilled drinks bubble more finely.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#气泡 #二氧化碳 #发酵
为什么牛奶能做成酸奶？
Why can milk become yogurt?
乳酸菌把牛奶里的乳糖发酵成乳酸，乳酸降低pH使酪蛋白凝固，牛奶就变成浓稠的酸奶。发酵还产生独特酸香风味并抑制有害菌。冷藏可减缓继续变酸。
Lactic-acid bacteria ferment the lactose in milk into lactic acid, which lowers the pH and makes casein coagulate, turning the milk into thick yogurt. Fermentation also creates a tangy flavor and suppresses harmful microbes. Refrigeration slows further souring.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#酸奶 #乳酸菌 #乳酸
为什么发酵保存的食物（如泡菜、酸奶）不容易坏？
Why do fermented foods like pickles and yogurt keep longer without spoiling?
发酵微生物（如乳酸菌）把糖变成乳酸等有机酸，降低了环境的 pH，多数腐败菌和致病菌在酸性下难以生存。同时产生的酒精、细菌素也抑制杂菌，于是食物更耐存放。
Fermenting microbes such as lactic-acid bacteria turn sugars into organic acids like lactic acid, lowering the environment's pH so most spoilage and pathogenic bacteria cannot thrive. The alcohol and bacteriocins also produced suppress competitors, extending shelf life.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
McGee《食物与烹饪》（On Food and Cooking 修订版），发酵章节
H. McGee, "On Food and Cooking" (rev. ed.), Ch. Fermentation
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL4110479W：On food and cooking（首版
#发酵保藏 #乳酸 #pH #乳酸菌
为什么米酒、黄酒有酒味？
Why do rice wine and huangjiu have an alcoholic taste?
酒曲中的酵母把米饭里的糖发酵成乙醇（酒精）和二氧化碳，于是有了酒味。不同酒曲和工艺决定酒精度和风味。加热会让酒精挥发，所以煮过的酒酿酒味变淡。
Yeast in the starter ferments the rice sugars into ethanol and carbon dioxide, giving the alcoholic note. Different starters and methods set the strength and flavor. Heating evaporates the alcohol, so cooked jiuniang tastes milder.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#米酒 #乙醇 #发酵
为什么泡菜、酸菜会变酸？
Why do pickles and sauerkraut turn sour?
蔬菜表面的乳酸菌在无氧环境下把糖分发酵成乳酸，积累起来就让菜变酸并得以保存。乳酸还能抑制腐败菌，所以泡菜能放较久。盐浓度和温度影响发酵快慢与风味。
Lactic-acid bacteria on the vegetable surface ferment sugars into lactic acid in an anaerobic environment, and its buildup makes the food sour and preservable. The acid also inhibits spoilage microbes, so pickles keep longer. Salt level and temperature shape the speed and flavor.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#泡菜 #乳酸发酵 #厌氧