| Pumpkins are nutritious and abundant in China,but fresh pumpkins are limited in fresh marketing due to their high moisture content and lack of storage and transportation,so it is important to develop pumpkin product markets to enhance the added value of pumpkins and promote local industrial development.In this paper,the main object of study is the Jinggangshan pumpkin,a characteristic pumpkin variety in Jiangxi,and four common pumpkin species(Beibei pumpkin,Miben pumpkin,Jingua pumpkin and Mopan pumpkin)are used as test reference objects to investigate the differences in appearance,flesh nutrition and flavour substances of the five pumpkin species.The fruit cakes were further developed for Jinggangshan pumpkin,and the optimal recipes for conventional Jinggangshan pumpkin cakes and sugar-free Jinggangshan pumpkin cakes were obtained by single-factor and orthogonal optimisation,using textural characteristics and sensory evaluation as evaluation indicators;and the effects of different drying methods on sugar-free pumpkin cakes were investigated.The specific results of the study are as follows:(1)There were differences in the physical characteristics,nutritional quality of the flesh and flavour of different varieties of pumpkin.The β-carotene,reducing sugar,total sugar,starch and dry matter content of Jinggangshan pumpkin were the highest;honeybourne pumpkin had the highest Vc content,pectin content and crude fibre content,followed by Jinggangshan pumpkin and the highest moisture content of mill pumpkin.Finally,the quality evaluation score of Jinggangshan pumpkin was 0.766 by principal component analysis,which was higher than that of Beibei pumpkin(0.545),Miben pumpkin(0.709),Jingua pumpkin(0.244)and Mopan pumpkin(0.277),indicating that Jinggangshan pumpkin has better feasibility for promotion.The volatile components of the flesh of the five pumpkin species were examined before and after maturation,and a total of 114 components were measured,including 5alkanes,20 aldehydes,15 olefins,10 esters,21 ketones,34 alcohols,2 acids and 7 other substances.Compared with the other four pumpkins,the unripe Jinggangshan pumpkin had more volatile substances,such as alkanes,aldehydes,olefins,esters,ketones and other volatile substances,than the other four unripe pumpkins;among the volatile components of the ripe Jinggangshan pumpkin,the number of alkanes,aldehydes,olefins,esters and ketones was comparable to that of the other four pumpkins,but the number of alcoholic volatile substances was significantly greater than that of the However,the alcohol volatiles were significantly greater than those of the other four pumpkin species,so the ripened Jinggangshan pumpkin had a stronger pumpkinspecific flavour.(2)The formulation of Jinggangshan pumpkin cake was optimised according to single-factor and orthogonal optimisation using hardness,stickiness,elasticity,chewiness,gumminess,chewiness and sensory evaluation as indicators.The optimal formulation of conventional pumpkin cake was obtained by single-factor and orthogonal optimisation: pumpkin pulp 300 g,sugar and maltose syrup 48 and 32 g respectively,and compound carrageenan 9 g.The resulting Jinggangshan pumpkin cake was orange-yellow in colour,glossy,transparent,fine in mouth,non-sticky,moderately hard and soft,with a strong pumpkin flavour,moderate sweetness,good gelatinisation,and evenly distributed overall.(3)By studying the rheological characteristics of the cake mixing system before drying and the microstructure after drying,the most suitable edible gum combination of carrageenan:konjac gum(2:1)and the most suitable sweetener steviol glycosides were obtained.The optimum recipe for cane sugar-free pumpkin cake was obtained according to single-factor and orthogonal optimisation: using pumpkin pulp as a reference for subsequent additions and set at 100%,the edible gum addition was 2%,the edible gum was carrageenan:konjac gum(2:1),the sweetener was steviol glycosides at 12% and the carboxymethyl cellulose(CMC)addition was 0.9%.The resulting cane sugar-free Jinggangshan pumpkin cake is orange-yellow in colour,glossy,transparent,fine in the mouth,not sticky,moderately soft and firm,with a strong pumpkin flavour,moderate sweetness,good gelation and overall uniform distribution.(4)The effects of heat pump drying,far-infrared drying and hot air drying on the drying rate,nutritional quality,colour and texture characteristics of cane sugar-free Jinggangshan pumpkin cake were investigated.The results showed that the drying time of the heat pump was the shortest(14 h)and the drying rate was significantly higher than that of the hot air drying and the far infrared drying;the L~*,b~* and a~* of the samples decreased after drying and the hot air drying had the greatest effect on the colour of the products;the colour of the samples was affected to the same extent by the heat pump and the far infrared drying;the texture analysis revealed that the samples dried by the hot air had the greatest hardness and viscosity,the samples dried by the far infrared had the greatest elasticity and chewiness,and the samples dried by the heat pump had the greatest chewiness.The sample dried by heat pump was in the middle of all the indexes,which resulted in a good texture of cane sugar-free Jinggangshan pumpkin cake. |
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