Analysisof B Vitaminsin Kiwifruitandtheirs External Effects

Kiwifruit(Actinidia.)is one of the most nutritious fruits.Its B vitamins are rich in variety,but B vitamins contents and their metabolic properties,the best intake period and the effect of exogenous B vitamins treatment on kiwifruit rarely reported.B vitamins are easily lost in body,resulting in the lack of B vitamins in the body.Usually sample chemical synthetic products was used to add B vitamins,chemical synthesised B vitamins easily over-assimilated,causing the liver and kidney metabolic overload and lead to human poisoning.In this paper,16 cultivated varieties of kiwifruit and 2 wild species were used to analyze the changes of B vitamins during fruit development and cold storage.At the same time,kiwifruit leaves were also treated with exogenous B vitamins during kiwifruit developmet,the changes of B vitamin contents in fruit,and the changes of major enzymes in the process of fruit ripening and senescence were studied.The results provide a theoretical basis for the physiological characteristics of B vitamins in kiwifruit,providethe optimum period of intakeB vitamins and study the treatment effects of exogenous B vitamins in kiwifruit.The main results are as follows:1.A method for the determination of 8 kinds of B vitamins in kiwifruit by high performance liquid chromatography(HPLC)was established.It used 270 nm and 210 nm double-wavelength detection,isocratic elution,a process of 27 min,can effectively separate and detect 8 kinds of B vitaminsin kiwifruit,they werethiamine(B1),riboflavin(B2),niacin(B3),pantothenic acid(B5),pyridoxine(B6),biotin(B7),folic acid(B9)and cobalamin(B12).2.The results showed that the peak of B vitamins were mainly found in the 3rd to the 6th period after blooming,which indicated that B vitamins had different physiological functions during different fruit growth and development periods.B vitamins were analyzed in 18 kiwifruit cultivars during postharvest period,such as ‘Hayward',‘Xuxiang',‘Hongyang' and so on.We discovered that picking period and and softing period had lower contents of B vitamins.Kiwifruit stored at refrigeration for one month had more kinds of B vitamins and higher contents,indicating that kiwifruit stored at refrigeration for one month was the most suitable period to intake B vitamins in kiwifruit.3.The B3 treatment increased the chlorophyll contents of kiwifruit leaves by using the exogenous B3 of 1 mg·L-1.For young leaves and fruit tissues,nicotinamide adenine dinucleotide phosphate content had a certain role in promoting the performance of mature fruits due to different varieties and performance.B3 treatment on ‘Hayward' and ‘Xuxiang'enhanced O contentin their young tissues and increased the activity of catalopyrogenase(CAT)in ‘Hayward',the formation of H2O2 in both ‘Hayward' and ‘Xuxiang' were inhibited.B3 treatment had little effect on the content of nicotinamide adenine dinucleotide in ‘Hayward' and ‘Xuxiang'.After treatment with B3,the peak of B vitamins in kiwifruit was advanced,and there was no significant effect on vitamin B contents in mature fruit.The results showed that B3 treatment could increase the activity of antioxidant enzymes in ‘Hayward' and ‘Xuxiang',which could be helpful to improve plant resistance.4.B2,B6 and B9 were used to treat different varieties of kiwi plant.It was found that 2 mmol·L-1 B2 treatment promoted the accumulation of flavin adenine dinuclear(FAD)in‘Jinnong-2'but not in ‘Jinxiang',the contents of flavonoid single nucleotide(FMN)in ‘Jinxiang' are also not affected.1 mg L-1 B6 promoted the accumulation of pyridoxal phosphate(PLP)in leaves of both ‘Cuiyu' and ‘Xuxiang'.In fruit,the promoted effect has only been found in ‘Xuxiang'.As for the effect on pyridoxal phosphate reductase(PLR)activity,the increased PLR activiey in‘Cuiyu'and ‘Xuxiang' fruit was found in the early and later stage of fruit development,respectivly.And the peak value of PLRactivity in‘Xuxiang' and ‘Cuiyu' leaves was postponed.Besides,the contents of B vitamins in kiwifruit was increased by the treatment of 1 mg L-1 B6.25 mg L-1 B9 treatment on ‘Jinkui' and ‘Xuxiang' promoted the increase of chlorophyll contents in young leaves and increased vitamin B contents in fruit.Moreover,it promoted the increase of folic acid contents in leaves of both ‘Xuxiang' and ‘Jinkui'.The results showed that treatment of these three vitamins could promote the peak of B vitamins in kiwifruit fruits,and B6 and B9 could be used to increase the contents of B vitamins in postharvest kiwifruit.5.B1,B5,B7 and B12 was applied on kiwi plant.The results showed that 1 mg ·L-1 B1 treatment enhanced the Pyruvate dehydrogenase activity in leaves of both ‘Xuxiang' and ‘Cuiyu' at different development stages.6 mg·L-1 B5 treatment increased coenzyme A(CoA)activity in their leaves.1 mg·L-1 B7 treatment increased the activity of pyrrole carboxylate(PC)and acetyl coenzyme A carboxylase(ACCcase)in ‘Jinkui' and ‘Miliang-1'.1 mg·L-1 B12 treatment reduced the contents of soluble protein in leaves of ‘Hayward' and ‘Xuxiang',and had no effect on the contents of B vitamins in kiwifruit.The B12 and B5 could promote the accumulation of B vitamins in kiwifruitduring the development stage,however,there was no obvious effect of B5,B7 and B12 treatment on the accumulation of B vitaminsduring the postharvest stages.The results showed that B5,B7 and B12 could not be used to enhance the B vitamins in the postharvest kiwifruit fruits.