Standardization and determination of marker compounds characterizing mature silkworm (Bombyx mori) powder

Here we report a specific method for the determination and validation of distinguishable standard marker compounds and processed mature silkworm powder with the aim of standardizing the powder to uniformly control it as a raw functional food ingredient. The content of three specific amino acids–serine, glycine, and alanine–were determined using high-performance liquid chromatography. The compounds met the requirement of marker compounds due to their unique repetitive amino acid sequence. The variations of the amounts of serine, glycine, and alanine in the powder were considered to depend on the cultivation and production conditions of the raw ingredient with the sum of three amino acid contents giving the unique quantitative marker compound level.     

Correlation between colloidal properties of ice cream mix and ice cream

Ice cream mix was produced with a range of emulsifiers and concentrations. Ice cream mix properties were measured and correlated to ice cream properties. Protein load (mg m⁻²) in ice cream mix correlated with major characteristic analyses describing the fat structure in ice cream (fat agglomerate size, fat agglomeration index, solvent extractable fat). Thus, the measurement of protein load in the mix can be used to predict ice cream fat stability and related structure with constant processing conditions. As emulsification increased, more fat could be seen at the air interface by scanning electron microscopy. High correlation coefficients were also obtained with fat structure analyses and the quantitative determination of fat in the dripped portion taken from a melting test of ice cream. Hence, fat analysis from the dripped melt fraction is suggested as a method to characterize the fat-related structure in ice cream.     

搅打奶油粉的制备及其在手工冰淇淋粉中的应用

以代可可脂、无水奶油、乳化剂为油相,葡萄糖浆、酪朊酸钠、K_2HPO_4以及胶体为水相,采用微胶囊技术喷雾干燥制备搅打奶油粉。结果表明,最佳工艺配方为代可可脂35%(占总固形物的质量分数,下同)、无水奶油5%、分子蒸馏单甘酯2%、乳酸脂肪酸甘油酯5%、丙二醇脂肪酸酯0. 6%、酪朊酸钠5%、K_2HPO_4 1%、琼脂0. 2%、葡萄糖浆(以固形物计) 46. 2%,制备的奶油粉添加2倍冷水搅打3 min即可成搅打奶油,打发倍数达到3. 3。按照搅打奶油粉24%,全脂粉30%,白砂糖45%,复配稳定剂1%制备成手打冰淇淋粉。制备的手工冰淇淋与市售产品比较,理化指标和感官品质方面表现均合格。对搅打奶油粉的配方及其应用进行了研究,极大提高了搅打奶油使用的方便性,扩展了其使用范围。     

Purification and characterization of a 6.5 kDa antioxidant peptidoglycan purified from silk worm (Bombyx mori) pupae extract

A unique antioxidant peptidoglycan of 6.5 kDa was purified from silk worm (Bombyx mori) pupae. The peptidoglycan was extracted and isolated from the acidified aqueous extract of the homogenized pupae by chloroform/methanol (2:1, v/v), and purified by size-exclusion chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC). This separation method allowed an easy and consistent preparation of the peptidoglycan from the high protein load by using only 3 steps of purification. The highly pure peptidoglycan consisted of fucose, glucosamine, galactosamine, glucose, and galactose as constituent sugars when revealed by high-performance anion exchange chromatography (HPAEC) analysis. The amino acid composition analysis showed the presence of acidic and polar amino acids (51.7%), hydrophobic (37.2%), and basic amino acids (9.3%) in the purified peptidoglycan. The IC₅₀ of the purified peptidoglycan was 0.22±0.05 and 0.61±0.09 μg for diphenyl-2-picryl hydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), respectively, as quantified by Ophthalaldehyde (OPA) microplate fluorescent assay.     

麦芽糊精替代脂肪对冰淇淋浆料流变学特性的影响

为了研究麦芽糊精替代脂肪对冰淇淋浆料流变学特性的影响,研究了麦芽糊精替代0%、25%、50%、75%脂肪的冰淇淋浆料的流动性、稠度和分子网络结构破坏、恢复等情况。结果表明,各替代率的浆料均属于假塑性流体,具有触变性,随脂肪替代率增大,浆料假塑性增强,稠度降低,流动性增大,屈服应力减小,浆料结构更容易被破坏。替代增强了浆料剪切结构恢复能力和热稳定性。0%、25%替代率浆料的G’、G″均明显大于50%、75%替代率,25%脂肪替代几乎不影响浆料G’,此外,替代增强了浆料G″对频率的依赖性,随频率增大显著上升。      

桔皮粉在冰淇淋中的应用研究

桔皮粉添加于冰淇淋或与黄原胶、瓜胶、海藻酸钠、明胶等复配，观察混合料的粘度、稳定性、冰淇淋的膨胀率及抗融性，结果表明：加桔皮粉的冰淇淋混合料粘度，除明胶外均低于其它稳定剂，但膨胀率、抗融性及稳定性均优于其它稳定剂。桔皮粉与其它胶体复配可显著提高明胶的作用，并能与黄原胶产生增效作用。     

Physicochemical,melting and sensory properties of ice cream incorporating processed ginger (Zingiber officinale)

Ginger juice and paste (from 2 to 8%, ginger candy from 5 to 20%, and ginger powder from 0.5 to 2%) were incorporated into the ice cream mix prior to freezing. Inclusion of the juice and paste reduced total solids, fat, protein and overrun, and increased antioxidant activity and phenols, whereas the ginger candy and powder increased solids, crude fibre, antioxidant activity and phenols, and diminished fat and overrun. Acidity increased with the ginger juice and powder, whereas it decreased with the ginger paste and candy. First dripping time amplified and melting rate declined with all the ginger preparations. Ice cream containing ginger juice, paste, candy and powder at 6, 4, 10 and 1%, respectively, achieved the highest overall acceptability scores.     

Selected nutritional quality and physicochemical properties of silkworm pupae (frozen or powdered) from two species

This research was performed to examine selected nutritional quality and physicochemical properties of silkworm pupae. Frozen or powdered pupae from two species of silkworm (Bombyx mori and Samia ricinii) were studied. Eri had the largest size with the highest lightness and peak viscosity. The PCA (principal component analysis) total variance could be explained by 74.68%, and silkworm pupaes could be put into 2 clusters. Cluster 1: all varieties of frozen silkworm pupae having a high moisture content; Cluster 2: silkworm pupae powder. Thai and Hybrid silkworm pupae powder had the highest calcium, total fat and n-3, n-6 and n-9 fatty acids. Eri silkworm pupae powder had the highest protein, essential amino acid and crude fibre. Each variety of silkworm pupae had different properties that might be suitable for developing different food products. Therefore, the presented data would be advantageous for manufacturers for developing functional ingredients and novel foods.     

大豆粉取代奶粉对冰淇淋品质的影响

在冰淇淋配方中以0~80%的大豆粉取代脱脂奶粉,对冰淇淋浆料进行了流变学、稳定性、粒度检测及对冰淇淋的膨胀率与抗融性进行测定,揭示了大豆粉的取代量对冰淇淋品质的影响。研究结果表明,随着大豆粉添加量的增加,冰淇淋浆料粘度显著增加,稳定性增强,而粒径差异不显著,针对于最终冰淇淋产品而言,其膨胀率呈现先上升(20%~40%)后下降(60%~80%)的趋势,但其抗融性逐渐增强,与此同时,豆味的表现也会加强,取代量大于60%时,豆香味则占主导。     

大豆粉取代奶粉对冰淇淋品质的影响

在冰淇淋配方中以0~80%的大豆粉取代脱脂奶粉,对冰淇淋浆料进行了流变学、稳定性、粒度检测及对冰淇淋的膨胀率与抗融性进行测定,揭示了大豆粉的取代量对冰淇淋品质的影响。研究结果表明,随着大豆粉添加量的增加,冰淇淋浆料粘度显著增加,稳定性增强,而粒径差异不显著,针对于最终冰淇淋产品而言,其膨胀率呈现先上升(20%~40%)后下降(60%~80%)的趋势,但其抗融性逐渐增强,与此同时,豆味的表现也会加强,取代量大于60%时,豆香味则占主导。      

Effects of BmKIT3R gene transfer on the development and survival of silkworm Bombyx mori

To verify the effects of gain-of-function mutation of the BmKIT3^R gene (from the Chinese scorpion Buthus martensii Karsch) on the development and survival rate of insects and to explore a novel strategy for pest control, the effects of BmKIT3^R gene transfer on the development and survival rate of silkworms were investigated. A novel transgenic vector derived from the piggyBac transposon with the BmKIT3^R gene controlled by the Bmhsp20.4 promoter was transferred into silkworm eggs. Transgenic silkworms were obtained after screening with GFP and G418 antibiotics and verification by PCR and dot hybridization. The results showed that the oviposition number decreased by 18.9%, and the hatching and final survival rates were approximately 63% and 47.5%, respectively. Some 18.9% of surviving pupae died before developing into moths in the G3 generation. A specific band corresponding to BmKIT3^R was detected for transgenic silkworms by Western blotting. This indicates that the Bmhsp 20.4 promoter has constitutive expression activity. The significant decrease in the survival rate suggests that pest population numbers could be effectively controlled by using BmKIT3^R gene transfer. Furthermore, it can be speculated that pupal development to moths could be blocked if BmKIT3^R were specially expressed in the pupal stage and reeling with fresh cocoons was performed.     

稳定剂对冰淇淋抗融性的影响

本文主要研究了稳定剂对冰淇淋抗融性的影响,确定了一个具有显著效果的稳定剂组合。     

Comparison of the effects of adding microbial transglutaminase to milk and ice cream mixture on the properties of ice cream

In this study, the effect of recombinant microbial transglutaminase enzyme on the physicochemical properties of ice cream produced by two different methods was investigated. For this purpose, different enzyme units (2, 4 and 6 U/g milk protein) were applied to both ice cream mixture and milk. While with the first method, a 10% increase in the overrun value of ice cream samples was observed, a 7% increase was obtained by the second method. All ice cream samples exhibited pseudoplastic behaviour. This study indicated that  transglutaminase concentration is an important factor in terms of improving the physicochemical properties of ice cream.