Publications by authors named "Tiankui Yang"

10 Publications

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Physicochemical properties of potato starch fermented by amylolytic Lactobacillus plantarum.

Int J Biol Macromol 2020 May 5;158:656-661. Epub 2020 May 5.

School of Agriculture and Biology, Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. Electronic address:

This study investigated the effect of fermentation by Lactobacillus plantarum CGMCC 14177 strain on physicochemical properties and morphological characteristics of potato starch. The maximum total amylase and α-amylase production of L. plantarum CGMCC 14177 were 286.8 and 208.1 U/g, respectively. Fermented granules clearly exhibited pocked and dimpled surfaces. The granule properties changed to have a 1.9% increase in relative crystallinity. Overall the starch changed to have slight increases in onset and peak temperature, but resulted decreases of conclusion temperature and enthalpy. Fermentation decreased peak viscosity and breakdown value, while increased trough viscosity, final viscosity, and setback. Further analysis showed that fermentation increased the gel hardness and chewiness of the potato starch, but made little differences in the springiness, cohesiveness and resilience. Collectively, these results provide insight on how Lactobacillus strains can be used to modify the physicochemical properties of potato starch in ways that extend its use in industrial applications.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.04.245DOI Listing
May 2020

Solid-state fermentation of palm kernels by Yarrowia lipolytica modulates the aroma of palm kernel oil.

Sci Rep 2019 02 22;9(1):2538. Epub 2019 Feb 22.

Food Science and Technology Programme, Department of Chemistry, National University of Singapore, Science Drive 3, Singapore, 117543, Singapore.

Solid-state fermentation with Yarrowia lipolytica was applied to palm kernels (PK) with the aim to modulate the aroma of palm kernel oil (PKO) obtained after kernel roasting. The results showed that, the metabolic activities of Y. lipolityca brought about significant changes to the volatile profile of obtained PKO either by providing thermal reaction reactants or by directly contributing aroma compounds. After fermentation, a decreased content in glucose (60%) while an elevated amount (7-fold) in free amino acids was found in PK, which further impacted the formation of volatile compounds by influencing the Maillard reaction and Strecker degradation during roasting. More Strecker aldehydes and N-heterocyclic compounds were formed in PKO derived from fermented PK especially after intensified roasting. In addition, the catabolism of Y. lipolytica imparted some distinct volatile compounds such as 2-phenylethanol to the obtained PKO. However, the lipase excreted by Y. lipolytica hydrolysed PK lipids and released 5-fold more free fatty acids in fermented PKO, relative to the blank and control PKO, which likely contributed to the off-flavor. On the basis of all volatile categories, principal component analysis (PCA) clearly separated the fermented PKO from the blank and control PKO, with light roasted, fermented PKO being correlated with acids, alcohols and aliphatic aldehydes; medium and dark roasted, fermented PKO tending to be dominated by pyrroles, pyrazines and furanones, which is in correspondence with sensory changes of PKO. This study demonstrated that combining fermentation with roasting could provide a novel way to modulate the volatile composition and aroma of PKO.
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http://dx.doi.org/10.1038/s41598-019-39252-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6384936PMC
February 2019

Viscozyme L pretreatment on palm kernels improved the aroma of palm kernel oil after kernel roasting.

Food Res Int 2018 05 14;107:172-181. Epub 2018 Feb 14.

Food Science and Technology Programme, Department of Chemistry, National University of Singapore, Science Drive 3, Singapore 117543, Singapore; National University of Singapore (Suzhou) Research Institute, No. 377 Linquan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China. Electronic address:

With an interest to enhance the aroma of palm kernel oil (PKO), Viscozyme L, an enzyme complex containing a wide range of carbohydrases, was applied to alter the carbohydrates in palm kernels (PK) to modulate the formation of volatiles upon kernel roasting. After Viscozyme treatment, the content of simple sugars and free amino acids in PK increased by 4.4-fold and 4.5-fold, respectively. After kernel roasting and oil extraction, significantly more 2,5-dimethylfuran, 2-[(methylthio)methyl]-furan, 1-(2-furanyl)-ethanone, 1-(2-furyl)-2-propanone, 5-methyl-2-furancarboxaldehyde and 2-acetyl-5-methylfuran but less 2-furanmethanol and 2-furanmethanol acetate were found in treated PKO; the correlation between their formation and simple sugar profile was estimated by using partial least square regression (PLS1). Obvious differences in pyrroles and Strecker aldehydes were also found between the control and treated PKOs. Principal component analysis (PCA) clearly discriminated the treated PKOs from that of control PKOs on the basis of all volatile compounds. Such changes in volatiles translated into distinct sensory attributes, whereby treated PKO was more caramelic and burnt after aqueous extraction and more nutty, roasty, caramelic and smoky after solvent extraction.
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http://dx.doi.org/10.1016/j.foodres.2018.02.023DOI Listing
May 2018

Celluclast 1.5L pretreatment enhanced aroma of palm kernels and oil after kernel roasting.

J Sci Food Agric 2017 Dec 29;97(15):5146-5157. Epub 2017 May 29.

Department of Chemistry, National University of Singapore, Singapore.

Background: The aroma of palm kernel oil (PKO) affects its applications. Little information is available on how enzymatic modification of palm kernels (PK) affects PK and PKO aroma after kernel roasting.

Results: Celluclast (cellulase) pretreatment of PK resulted in a 2.4-fold increment in the concentration of soluble sugars, with glucose being increased by 6.0-fold. Higher levels of 1.7-, 1.8- and 1.9-fold of O-heterocyclic volatile compounds were found in the treated PK after roasting at 180 °C for 8, 14 and 20 min respectively relative to the corresponding control, with furfural, 5-methyl-2-furancarboxaldehyde, 2-furanmethanol and maltol in particularly higher amounts. Volatile differences between PKOs from control and treated PK were also found, though less obvious owing to the aqueous extraction process. Principal component analysis based on aroma-active compounds revealed that upon the proceeding of roasting, the differentiation between control and treated PK was enlarged while that of corresponding PKOs was less clear-cut. Celluclast pretreatment enabled the medium roasted PK to impart more nutty, roasty and caramelic odor and the corresponding PKO to impart more caramelic but less roasty and burnt notes.

Conclusion: Celluclast pretreatment of PK followed by roasting may be a promising new way of improving PKO aroma. © 2017 Society of Chemical Industry.
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http://dx.doi.org/10.1002/jsfa.8394DOI Listing
December 2017

Effects of germination on the nutritional properties, phenolic profiles, and antioxidant activities of buckwheat.

J Food Sci 2015 May 9;80(5):H1111-9. Epub 2015 Apr 9.

Wilmar (Shanghai) Biotechnology Research and Development Center Co., Ltd, No. 118 Gaodong Rd., Pudong New District, Shanghai, 200137, China.

Germination is considered to be an effective process for improving the nutritional quality and functionality of cereals. In this study, changes of nutritional ingredients, antinutritional components, chemical composition, and antioxidant activities of buckwheat seeds over 72 h of germination were investigated, and the reasons for these changes are discussed. With the prolonged germination time, the contents of crude protein, reducing sugar, total phenolics, total flavonoids, and condensed tannins increased significantly, while the levels of crude fat, phytic acid, and the activity of trypsin inhibitor decreased. Phenolic compounds, such as rutin, vitexin, isovitexin, orientin, isoorientin, chlorogenic acid, trans-3-hydroxycinnamic acid, and p-hydroxybenzoic acid increased significantly during the germination process, which may be due to the activation of phenylalanine ammonialyase. The improvement of flavonoids led to significant enhancement of the antioxidant activities of germinated buckwheat. Germinated buckwheat had better nutritional value and antioxidant activities than ungerminated buckwheat, and it represented an excellent natural source of flavonoids and phenolic compounds, especially rutin and C-glycosylflavones. Therefore, germinated buckwheat could be used as a promising functional food for health promotion.
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http://dx.doi.org/10.1111/1750-3841.12830DOI Listing
May 2015

Enzymatic synthesis of feruloylated lysophospholipid in a selected organic solvent medium.

Food Chem 2013 Dec 13;141(4):3317-22. Epub 2013 Jun 13.

School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, People's Republic of China.

Feruloylated lysophospholipids (FLPs) were firstly synthesized from phosphatidylcholine (PC) and ethyl ferulate (EF) using lipase-catalysed interesterification in selected solvents at controlled water content. Kinds of lipases and single solvents were screened. Novozym 435 and toluene were found to be the suitable biocatalyst and solvent, respectively. Then tert-butanol, n-butanol, chloroform, isopropanol, acetone and DMSO were respectively added into toluene in order to increase conversion of products. The results showed that toluene/chloroform could significantly increase the conversion and the optimal combination of toluene and chloroform was 90:10 (v/v). The optimal conditions generated for FLPs production were a substrate molar ratio of 5:1 (PC/EF), a PC's hydrolytic time of 1.5h, an enzyme load of 60 mg/ml, a solvent dosage of 5 ml and a molecular sieves concentration (4Å) of 100mg/ml. Under these conditions, 40.51% of EF can be converted to FLPs, which were identified by TLC and HPLC-MS.
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http://dx.doi.org/10.1016/j.foodchem.2013.06.012DOI Listing
December 2013

Lipases as biocatalysts for the synthesis of structured lipids.

Methods Mol Biol 2012 ;861:403-33

Wilmar Global R&D Center, Shanghai, China.

Structured lipids (SL) are broadly referred to as modified or synthetic oils and fats or lipids with functional or pharmaceutical applications. Some structured lipids, such as triglycerides that contain both long-chain (mainly essential) fatty acids and medium- or short-chain fatty acids and also artificial products that mimic the structure of natural materials, namely human milk fat substitutes and cocoa butter equivalents, have been discussed. Further, other modified or synthetic lipids, such as structured phospholipids and synthetic phenolic lipids are also included in this chapter. For all the products described in this chapter, enzymatic production in industry has been already conducted in one way or another. Cocoa butter equivalents, healthy oil containing medium-chain fatty acids, phosphatidyl serine, and phenol lipids from enzyme technology have been reported for commercial operation. As the demand for better quality functional lipids is increasing, the production of structured lipids becomes an interesting area. Thus, in this chapter we have discussed latest developments as well as present industrial situation of all commercially important structured lipids.
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http://dx.doi.org/10.1007/978-1-61779-600-5_23DOI Listing
July 2012

[Advances in biodiesel research].

Sheng Wu Gong Cheng Xue Bao 2010 Jul;26(7):892-902

School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China.

Biodiesel is renewable and environmentally friendly; however, there are still many challenges for its commercial production as an alternative of petroleum-based transportation fuels, particularly in China with very limited resources for its biofuels development. In this article, the update progress of biodiesel R & D and production is reviewed, with a focus on its feedstock supply, manufacturing processes, quality control and byproduct utilization. It is concluded that the strategy of biorefinery to ultimately explore feedstock potentials will make biodiesel production more economically competitive.
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July 2010

Enzymatic interesterification of butterfat with rapeseed oil in a continuous packed bed reactor.

J Agric Food Chem 2005 Jul;53(14):5617-24

BioCentrum-DTU, Technical University of Denmark, Lyngby, Denmark.

Lipase-catalyzed interesterification of butterfat blended with rapeseed oil (70/30, w/w) was investigated both in batch and in continuous reactions. Six commercially available immobilized lipases were screened in batch experiments, and the lipases, Lipozyme TL IM and Lipozyme RM IM, were chosen for further studies in a continuous packed bed reactor. TL IM gave a fast reaction and had almost reached equilibrium with a residence time of 30 min, whereas RM IM required 60 min. The effect of reaction temperature was more pronounced for RM IM. TL IM showed little effect on the interesterification degree when the temperature was raised from 60 degrees C to 90 degrees C, whereas RM IM had a positive effect when the temperature was increased from 40 degrees C to 80 degrees C. Even though TL IM is an sn-1,3 specific lipase, small changes in the sn-2 position of the triacylglycerol could be seen. The tendency was toward a reduction of the saturated fatty acid C14:0 and C16:0 and an increase of the long-chain saturated and unsaturated fatty acids (C18:0 and C18:1), especially at longer residence times (90 min). In prolonged continuous operation the activity of TL IM was high for the first 5 days, whereafter it dramatically decreased over the next 10 days to an activity level of 40%. In general, the study shows no significant difference for butterfat interesterification in terms of enzyme behavior from normal vegetable oils and fats even though it contains short-chain fatty acids and cholesterol. However, the release of short-chain fatty acids from enzymatic reactions makes the sensory quality unacceptable for direct edible applications.
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http://dx.doi.org/10.1021/jf050646gDOI Listing
July 2005

Enzymatic production of monoacylglycerols containing polyunsaturated fatty acids through an efficient glycerolysis system.

J Agric Food Chem 2005 Mar;53(5):1475-81

BioCentrum-DTU, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.

The aim of the study was to develop an efficient glycerolysis system for the enzymatic production of monoacylglycerols (MAGs) containing polyunsaturated fatty acids. Glycerolysis has been widely applied in industry for the chemical production of food MAGs under high temperature. The enzymatic glycerolysis system at 40-70 degrees C is unfortunately a multiphase system, which leads to the lower reaction efficiency. A tert-butyl alcohol system was developed after careful evaluation and more than 20-fold of the reaction efficiency from this system was obtained compared to the solvent-free system. Novozym 435 was employed as a catalyst in the glycerolysis from the screening. In the batch reaction system with tert-butyl alcohol, temperature higher than 40 degrees C was favored. The glycerol/oil ratio was best in the study with 4.5 while the solvent weight ratio from 1 to 3 had little effect. In general, 60-70% yield can be obtained at 2 h in the stirred tank reactor. The continuous glycerolysis was conducted in a packed bed reactor. MAG yield up to 70% was reached at 30-40 min residence time. The continuous glycerolysis was more sensitive to the amount of tert-butyl alcohol, and in the weight ratio to oil more than 2 was favored. The continuous process was optimized with the assistance of response surface methodology. Optimal conditions for the packed bed reactor after all considerations were recommended as glycerol/oil 4:1 (mol/mol), temperature 40 degrees C, and residence time 45 min. The operation stability study showed that there was no slight reduction of reaction performance at more than 30 days, implying a high feasibility in practical applications.
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http://dx.doi.org/10.1021/jf048405gDOI Listing
March 2005