Studies On Brewing Technology,flavor Components And Antioxidant Activity Of Mead

Honeys are recognized as the natural nutrition all over the word.They are flavored by the vast number of consumers because of special nutritional and flavor.Mead is low-alcohol,the honey is diluted and inoculated with the appropriate yeast for fermentation.At present,there are many researches about mead,but the researches about flavor components and antioxidant are relatively small.This paper regards buckwheat honey,apocynum honey,sunflower honey,motherwort honey,gallnut honey,citrus honey and acacia honey as the research objects from Chongqing Three Gorges.The response surface methodology was used to optimize the fermentation process,and the favor components and antioxidant of the meads were compared.The conclusions are as follows:1.The Acacia honey as raw materials,the mead was brewed with excellent C yeast.The conditions such as added yeast amount,initial sugar degree,initial pH and nutrient addition were investigated to understand their effects on fermentation.Single factor experiments and Box-Behnken matrix design were used to establish a quadratic regression mode and response surface analysis was carried out for optimization.The optimum fermentation conditions were determined as follows: sugar degree of 24%,yeast inoculation of 0.2%,yeast energizer amount of 0.5 g/L and fermentation time 10 d,under the conditions the alcohol content was 11.7%?v/v?.2.The volatile components of seven honeys samples were detected by GC-MS,and 146 substances were detected.Buckwheat honey,apocynum honey,sunflower honey,motherwort honey,gallnut honey,citrus honey and acacia honey were detected respectively 48,42,52,40,58,45,46.The volatile components of 7 kinds of honey were mainly ester,alcohol,aldehydes and ketones.Cis-oxidation of linalool,phenylethyl alcohol,trans-oxidation of linalool,2,3-dihydro-3,5-dihydroxy-6-methyl-4?4H?-pyridone,ethyl phenylacetate,octanoic acid Ethyl ester,ethyl decanoate,ethyl oleate were the most important aroma components of 7 kinds of honeys.3.The volatile components of meads were detected by GC-MS,and 230 substances were detected.Buckwheat,Apocynum,Sunflower,Motherwort,Gallnut,Citrus and Acacia were detected respectively 80,83,89,70,81,95,90.7 kinds of meads alcohols were mainly isoamyl alcohol and phenylethyl alcohol,esters wree mainly ethyl octanoate,ethyl caprate and ethyl laurate.Isoamyl alcohol,phenylethyl alcohol,ethyl octanoate,ethyl decanoate,octanoic acid were the main main aroma substancesof meads,but the content of them was quite different.The comparisons of the total aroma amounts and the content of each component in 7 meads were made,and the result showeg that they also contained a few particular aroa components.These components lead to a similar and unique aroma and style for mead.4.Among the 7 kinds of honey,17 kinds of amino acids were only detected in buckwheat honey,the highest content of amino acids was gallnut honey,the content was 606.74 mg / L,the lowest content of acorn honey was 71.64 mg /L.The total content of amino acids in meads was between 44.61mg/L and 258.59 mg/L.The highest was the sunflower wine,the lowest content was acacia wine.Proline was the main free amino acid in mead and the content was between 40.733 mg / L and 233.46 mg / L.In 7 kinds of mead,the sweet taste of amino acids were mian component and the content of was more than 90.00%,followed by bitterness.The linear regression equation of total amino acid?y?and proline?x?was established: y = 1.1559 x + 4.448.5.7 Organic acids were detected by high performance liquid chromatography?HPLC?: oxalic acid,tartaric acid,pyruvic acid,lactic acid,acetic acid,citric acid and succinic acid.The total amount was between 4.829 g / L and 7.903 g / L,acetic acid and succinic acid were main organic acids.Through analyzing the flavor intensity of organic acids in 7 kinds of mead,the flavor intensity of lactic acid and acetic acid was the strongest and they were an important taste of organic acids in mead.6.After the honeys finished fermention,the total number of aromas increased,amino acid content decreased except sunflower.7.Through the principal component analysis of 7 kinds of meads flavor substances,getting the computational formula of comprehensive evaluation aroma substances of in mead: F=0.5524F1+ 0.2508F2+ 0.1967F3,the score order was: Citrus>Acacia> Motherwort>Buckwheat>Sunflower>Apocynum> Gallnut.The computational formula of comprehensive evaluation of amino acids in mead was F=0.565F1+0.222F2+0.141F3 + 0.072F4.The score order was: Sunflower>Apocynum>Acacia>Gallnut> Motherwort>Buckwheat>Citrus,the computational formula of comprehensive evaluation of organic acid in mead was F=0.633F1+0.367F2,the score order was: Sunflower> Buckwheat> Gallnut> Motherwort>Apocynum>Citrus> Acacia.The score order of sensory was: Citrus>Acacia>Buckwheat>Motherwort>Sunflower> Apocynum>Gallnut.Thought the three principal component analysis?PCA?and sensory scores,the aroma model was considered to be the most reliable,and the citrus,buckwheat and acacia honey were considered to be best orign for mead.8.The antioxidation ability of different meads was significant differences.The order of total antioxidant activity was: Buckwheat> Apocynum> Sunflower> Gallnut> Motherwort> Citrus> Acacia.The scavenging ability of DPPH,O₂^-and OH increased after fermentation,but ABTS⁺·scavenging ability decreased,Fe3 + reduction power and total antioxidant capacity decreased.The polyphenol,organic acid,chroma and ability to scavenge DPPH,ABTS⁺,Fe³⁺reduction power,total antioxidant capacity had a significant positive correlation...