A Rationally Designed CRISPR/Cas12a Assay Using a Multimodal Reporter for Various Readouts.

The CRISPR/Cas systems offer a programmable platform for nucleic acid detection, and CRISPR/Cas-based diagnostics (CRISPR-Dx) have demonstrated the ability to target nucleic acids with greater accuracy and flexibility. However, due to the configuration of the reporter and the underlying labeling mechanism, almost all reported CRISPR-Dx rely on a single-option readout, resulting in limitations in end-point result readouts. This is also associated with high reagent consumption and delays in diagnostic reports due to protocol differences. Herein, we report for the first time a rationally designed Cas12a-based multimodal universal reporter (CAMURE) with improved sensitivity that harnesses a dual-mode reporting system, facilitating options in end-point readouts. Through systematic configurations and optimizations, our novel universal reporter achieved a 10-fold sensitivity enhancement compared to the DETECTR reporter. Our unique and versatile reporter could be paired with various readouts, conveying the same diagnostic results. We applied our novel reporter for the detection of staphylococcal enterotoxin A due to its high implication in staphylococcal food poisoning. Integrated with loop-mediated isothermal amplification, our multimodal reporter achieved 10 CFU/mL sensitivity and excellent specificity using a real-time fluorimeter, in-tube fluorescence, and lateral flow strip readouts. We also propose, using artificially contaminated milk samples, a fast (2-5 min) Triton X-100 DNA extraction approach with a comparable yield to the commercial extraction kit. Our CAMURE could be leveraged to detect all gene-encoding SEs by simply reprogramming the guide RNA and could also be applied to the detection of other infections and disease biomarkers.

Effect of sodium chloride concentration on off-flavor removal correlated to glucosinolate degradation and red radish anthocyanin stability.

Anthocyanin-rich concentrates from different red radish can be used as natural food colorants. However, the development of off-flavor during extraction has been major challenge in processing industries. This work aimed to evaluate the effect of sodium chloride (NaCl) concentration in phosphoric acidified medium pH 2.5 on removal of off-flavor from red radish anthocyanin. The effect of NaCl concentration on anthocyanin properties was also evaluated. Results showed that the total glucosinolate was highly degraded at high NaCl concentration (< 500 mM) compared with control, leading to higher off-flavor development. Additionally, the glucosinolate degradation was positively and significantly correlated to isothiocyanate, while was negatively and significantly correlated with dimethyl di-, trisulfide, cedrol, triacetin, 6-methyl-5-hepten-2-one. Moreover, total monomeric and color properties of extracted anthocyanins were degraded at high NaCl concentration (< 500 mM) compared with control. The tentative anthocyanin identification by UPLC-TQ-MS showed 12 glycosylated anthocyanins substituted at C3 and C5 in tested anthocyanin extracts. In conclusion, higher NaCl concentration (< 500 mM) could not be useful for red radish off-flavor removal and anthocyanin properties.

Correlating enzymatic browning inhibition and antioxidant ability of Maillard reaction products derived from different amino acids.

BACKGROUND: Up to now, only limited research on enzymatic browning inhibition capacity (BIC) of Maillard reaction products (MRPs) has been reported and there are still no overall and systematic researches on MRPs derived from different amino acids. In the present study, BIC and antioxidant capacity, including 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and Fe2+ reducing power activity, of the MRPs derived from 12 different amino acids and three reducing sugars were investigated. RESULTS: The MRPs of cysteine (Cys), cystine, arginine (Arg) and histidine (His) showed higher BIC compared to other amino acids. Lysine (Lys)-MRPs showed the highest absorbance value at 420 nm (A420 ) but very limited BIC, whereas Cys-MRPs, showed the highest BIC and the lowest A420 . The A420 can roughly reflect the trend of BIC of MRPs from different amino acids, except Cys and Lys. MRPs from tyrosine (Tyr) showed the most potent antioxidant capacity but very limited BIC, whereas Cys-MRPs showed both higher antioxidant capacity and BIC compared to other amino acids. Partial least squares regression analysis showed positive and significant correlation between BIC and Fe2+ reducing power of MRPs from 12 amino acids with glucose or fructose, except Lys, Cys and Tyr. The suitable pH for generating efficient browning inhibition compounds varies depending on different amino acids: acidic pH was favorable for Cys, whereas neutral and alkaline pH were suitable for His and Arg, respectively. Increasing both heating temperature and time over a certain range could improve the BIC of MRPs of Cys, His and Arg, whereas any further increase deteriorates their browning inhibition efficiencies. CONCLUSION: The types of amino acid, initial pH, temperature and time of the Maillard reaction were found to greatly influence the BIC and antioxidant capacity of the resulting MRPs. There is no clear relationship between BIC and the antioxidant capacity of MRPs when reactant type and processing parameters of the Maillard reaction are considered as variables. © 2017 Society of Chemical Industry.

Contribution of crosslinking products in the flavour enhancer processing: the new concept of Maillard peptide in sensory characteristics of Maillard reaction systems.

In this study, the flavour-enhancing properties of the Maillard reaction products (MRPs) for different systems consisted of different peptides (sunflower, SFP; corn, CP and soyabean SP) with, xylose and cysteine were investigated. Maillard systems from peptides of sunflower, corn and soyabean with xylose and cysteine were designated as PXC, MCP and MSP, respectively. The Maillard systems were prepared at pH of 7.4 using temperature of 120C for 2 h. Results showed that all systems were significantly different in all sensory attributes. The highest scores for mouthfulness and continuity were observed for MCP with the lowest peptides distribution between 1000 and 5000 Da, known as Maillard peptide. This revealed that the MCP with the lowest Maillard peptide content had the strongest "Kokumi" effect compared to the other MRPsand demonstrated that "kokumi effect" of MRPs was contributed by not only the "Maillard peptide" defined by the molecular weight (1000-5000 Da). Results on sensory evaluation after fractionation of PXC followed by enzymatic hydrolysis showed no significant differences between PXC, P-PXC and their hydrolysates. This observation therefore confirmed that the presence of other contributors attributed to the "Kokumi" effect rather than the Maillard peptide. It can be deduced that the unhydrolyzed crosslinking products might have contributed to the "Kokumi" effect of MRPs. The structures of four probable crosslinking compounds were proposed and the findings have provided new insights in the sensory characteristics of xylose, cysteine and sunflower peptide MRPs.

Comparation sensory characteristic, non-volatile compounds, volatile compounds and antioxidant activity of MRPs by novel gradient temperature-elevating and traditional isothermal methods.

A novel gradient temperature-elevating Maillard reaction was developed to effectively produce light-colored MRPs. The main purpose of the present study was to compare the color, taste characteristic, non-volatile compounds, volatile compounds and antioxidant activity of MRPs prepared by the novel gradient temperature-elevating and traditional isothermal methods. The product prepared from soybean peptide, D-xylose and L-cysteine by gradient temperature-elevating method was termed MRP-60. Isothermal method was used to produce light and dark colored MRP, called PXC and PX, respectively. MRP-60 has not only the lowest brown intensity (A420, 0.088), also the highest overall acceptability taste from sensory evaluation. MRP-60 showed the lowest bitterness which could be attributed to the lowest content of bitter amino acids (1.48 mg/ml); MRP-60 also showed indistinctive mouthfulness compared with PXC which elucidated by the percentage of compounds with a molecular weight of 1,000-5,000 Da (15.03 %) and high antioxidant activity. Then, the MRPs prepared by gradient temperature-elevating method successfully attain desirable taste and high antioxidant activity.

Contribution of tobacco composition compounds to characteristic aroma of Chinese faint-scent cigarettes through chromatography analysis and partial least squares regression.

To further explore the aroma mechanism of Chinese faint-scent cigarettes, the contribution of tobacco leaf composition, including six kinds of saccharides, eight tobacco alkaloids, seventeen kinds of organic acids, eighteen kinds of amino acids and four ions (Na+, K+, Mg2+ and Ca2+), on aroma quality characteristic (freshness, flowery and acidic notes) of faint-scent cigarettes was analyzed by chromatography and PLSR. The results showed that (i) xylose, fructose, glucose, maltose and sucrose were negatively correlated to acidic note, while galactose showed significantly positive correlation to acidic note. (ii) Phenylalanine and proline showed significant and positive correlation with characteristic aromas. Proline contributed to freshness and flowery, while leucine significantly contributed to acidic note. (iii) Most organic acids were significantly correlated to characteristic aromas. Palmitic acid and stearic acid contributed to the freshness, while dodecanoic acid and palmitic acid significantly contributed to flowery. (iv) Tobacco Na ion plays negative and significant correlation to acidic note.

Sodium sulfite pH-buffering effect for improved xylose-phenylalanine conversion to N-(1-deoxy-d-xylulos-1-yl)-phenylalanine during an aqueous Maillard reaction.

The yield of the Maillard reaction intermediate (MRI), prepared in aqueous medium, is usually unsatisfactory. However, the addition of sodium sulfite could improve the conversion of xylose-phenylalanine (Xyl-Phe) to the MRI (N-(1-deoxy-d-xylulos-1-yl)-phenylalanine) in aqueous medium. Sodium sulfite (Na2SO3) showed a significant pH-buffering effect during the Maillard reaction, which accounted for its facilitation of the N-(1-deoxy-d-xylulos-1-yl)-phenylalanine yield. The results revealed that the pH could be maintained at a relatively high level (above 7.0) for an optimized pH-buffering effect when Na2SO3 (4.0%) was added before the reaction of Xyl-Phe. Thus, the conversion of Xyl-Phe to N-(1-deoxy-d-xylulos-1-yl)-phenylalanine increased from 47.23% to 74.86%. Furthermore, the addition moment of Na2SO3 and corresponding solution pH were crucial factors in regulating the pH-buffering effect of Na2SO3 on N-(1-deoxy-d-xylulos-1-yl)-phenylalanine yield. Based on the pH-buffering effect of Na2SO3 and maintaining the optimal pH 7.4 relatively stable, the conversion of Xyl-Phe to N-(1-deoxy-d-xylulos-1-yl)-phenylalanine was successfully improved.

A new approach for facile synthesis of phytosteryl phenolates.

In this study, a one-step method for producing phytosteryl phenolates, namely phytosteryl cinnamate and ferulate, has been successfully developed and their chemical structures were confirmed by FT-IR, MS and NMR. The highest yield of phytosteryl ferulate (85.7%) was obtained at 100 °C for 2 h after optimization. A Lewis acid catalyst scandium triflate was selected as the catalyst, and it turned out that it could be reused for at least five times without significant loss of activity. Meanwhile, it has been demonstrated that the solubility of phytosteryl phenolates in soybean oil was much higher than in both phenolic acid and phytosterol, which was conducive to expand their applications in oil-based food. The research finding helps realize convenient, green and efficient synthesis of phytosteryl phenolates.

Enzymatic synthesis of phytosteryl lipoate and its antioxidant properties.

In this work, an enzymatic route for synthesizing phytosteryl lipoate was successfully set up for the first time. The structure of final product phytosteryl lipoate was determined by Fourier Transform Infrared (FTIR), Mass Spectrometry (MS) and Nuclear Magnetic Resonance (NMR). The maximum conversion of 71.2% was achieved when the following conditions were employed: 150mmol/L phytosterol, 1: 2.5M ratio of phytosterol to lipoic acid, 10g/L of 4Å molecular sieves and 60g/L Candida rugosa in 2-methyl-2-butanol/n-hexane (1:1, v/v) at 55°C for 96h. The physicochemical properties including solubility and antioxidant ability of phytosteryl lipoate in oil were assessed. The results revealed that phytosteryl lipoate possessed over twice as much oil solubility as free phytosterol and also showed better antioxidant ability. Investigation on its biological functions will be the main object in the future work.

Investigating the optimum conditions for minimized 3-chloropropane-1,2-diol esters content and improved sensory attributes during savory beef flavor preparation.

In this study, the effects of enzymatic hydrolysis of tallow and addition of sodium chloride (NaCl) were evaluated on the formation of 3-monochloropropane-1,2-diol (3-MCPD) esters and sensory characteristic of beef flavors. The enzymatic hydrolysis condition had significant effects on 3-MCPD mono/di-esters formation during the beef flavor preparation. Considering the safety and sensory characteristics of beef flavors, the optimal enzymatic hydrolysis conditions were selected as: lipase concentration 75U/g tallow, tallow concentration 80% (w/v) and pH 7.0 at 47.5°C for 9.5h. Using the optimal enzymatic hydrolysis conditions, no 3-MCPD monoesters were detected and 3-MCPD-diesters concentration was strongly dependent on NaCl concentration and its addition moment (before or after thermal reaction) at different temperatures. In conclusion, beef flavor was prepared using the optimal hydrolysis conditions and heated at 110°C for 100min, then 10% NaCl was added when the system was cooled to 60°C.

A class-specific artificial receptor-based on molecularly imprinted polymer-coated quantum dot centers for the detection of signaling molecules, N-acyl-homoserine lactones present in gram-negative bacteria.

Herein, a novel class-specific artificial receptor-based on molecularly imprinted polymer (MIP)-coated quantum dots (QDs@MIP) was synthesized, characterized, and used for the detection and quantification of the bacterial quorum signaling molecules N-acyl-homoserine lactones (AHLs), a class of autoinducers from Gram-negative bacteria. The QDs@MIP was prepared by surface imprinting technique under controlled conditions using CdSe/ZnS QDs as the signal transducing material. The synthesis of the QDs@MIP was characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis, and fluorescence spectroscopy. After template elution, the obtained cavities sensitively and selectively recognized the target AHLs of interest. The fluorescence intensity of the QDs@MIP was significantly quenched compared to the control non-imprinted polymer (QDs@NIP) upon exposure to different AHL concentrations. It also had a good linearity in the range from 2 to 18 nM along with a detection limit of 0.66, 0.54, 0.88, 0.72 and 0.68 nM for DMHF, C4-HSL, C6-HSL, C8-HSL and N-3oxo-C6-HSL, respectively. Most interestingly, the proposed sensor exhibited high sensitivity, good stability and fast response (30 s) towards the target molecules due to successful formation of surface imprints. The practicability of the developed sensor in real samples was further confirmed through the analysis of bacterial supernatant samples with satisfactory recoveries ranging from 89 to 103%. According to these results, the as-prepared QDs@MIP can be used as a new potential supporting technique for the rapid and real-time detection of bacterial pathogens in food safety and healthcare facilities.

Mechanism of Formation and Stabilization of Nanoparticles Produced by Heating Electrostatic Complexes of WPI-Dextran Conjugate and Chondroitin Sulfate.

Protein conformational changes were demonstrated in biopolymer nanoparticles, and molecular forces were studied to elucidate the formation and stabilization mechanism of biopolymer nanoparticles. The biopolymer nanoparticles were prepared by heating electrostatic complexes of whey protein isolate (WPI)-dextran conjugate (WD) and chondroitin sulfate (ChS) above the denaturation temperature and near the isoelectric point of WPI. The internal characteristics of biopolymer nanoparticles were analyzed by several spectroscopic techniques. Results showed that grafted dextran significantly (p < 0.05) prevented the formation of large aggregates of WD dispersion during heat treatment. However, heat treatment slightly induced the hydrophobicity changes of the microenvironment around fluorophores of WD. ChS electrostatic interaction with WD changed the fluorescence intensity of WD regardless of heat treatment. Far-UV circular dichroism (CD) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopies confirmed that glycosylation and ionic polysaccharide did not significantly cause protein conformational changes in WD and ChS (WDC) during heat treatment. In addition, hydrophobic bonds were the major molecular force for the formation and stabilization of biopolymer nanoparticles. However, hydrogen bonds slightly influenced their formation and stabilization. Ionic bonds only promoted the formation of biopolymer nanoparticles, while disulfide bonds partly contributed to their stability. This work will be beneficial to understand protein conformational changes and molecular forces in biopolymer nanoparticles, and to prepare the stable biopolymer nanoparticles from heating electrostatic complexes of native or glycosylated protein and polysaccharide.

Cardioprotective effects of lipoic acid, quercetin and resveratrol on oxidative stress related to thyroid hormone alterations in long-term obesity.

This study investigated possible mechanisms for cardioprotective effects of lipoic acid (LA), quercetin (Q) and resveratrol (R) on oxidative stress related to thyroid hormone alterations in long-term obesity. Female C57BL/6 mice were fed on high-fat diet (HFD), HFD+LA, HFD+R, HFD+Q and normal diet for 26weeks. Body weight, blood pressure, thyroid hormones, oxidative stress markers, angiotensin converting enzyme (ACE), nitric oxide synthase (NOS) and ion pump activities were measured, and expression of cardiac genes was analyzed by real-time polymerase chain reaction. HFD induced marked increase (P<.05) in body weight, blood pressure and oxidative stress, while plasma triidothyronine levels reduced. ACE activity increased (P<.05) in HFD mice (0.69±0.225U/mg protein) compared with controls (0.28±0.114U/mg protein), HFD+LA (0.231±0.02U/mg protein) and HFD+Q (0.182±0.096U/mg protein) at 26weeks. Moreover, Na(+)/K(+)-ATPase and Ca(2+)-ATPase activities increased in HFD mice whereas NOS reduced. A 1.5-fold increase in TRα1 and reduction in expression of the deiodinase iodothyronine DIO1, threonine protein kinase and NOS3 as well as up-regulation of AT1α, ACE, ATP1B1, GSK3ß and Cja1 genes also occurred in HFD mice. Conversely, LA, Q and R inhibited weight gain; reduced TRα1 expression as well as increased DIO1; reduced ACE activity and AT1α, ATP1B1 and Cja1 gene expression as well as inhibited GSK3ß; increased total antioxidant capacity, GSH and catalase activity; and reduced blood pressure. In conclusion, LA, resveratrol and quercetin supplementation reduces obesity thereby restoring plasma thyroid hormone levels and attenuating oxidative stress in the heart and thus may have therapeutic potential in heart diseases.

Fabrication of polymeric nanocapsules from curcumin-loaded nanoemulsion templates by self-assembly.

In this study, biodegradable polymeric nanocapsules were prepared by sequential deposition of food-grade polyelectrolytes through the self-assembling process onto the oil (medium chain triglycerides) droplets enriched with curcumin (lipophilic bioactive compound). Optimum conditions were used to prepare ultrasound-assisted nanoemulsions stabilized by octenyl-succinic-anhydride (OSA)-modified starch. Negatively charged droplets (-39.4 ± 1.84 mV) of these nanoemulsions, having a diameter of 142.7 ± 0.85 nm were used as templates for the fabrication of nanocapsules. Concentrations of layer-forming cationic (chitosan) and anionic (carboxymethylcellulose) biopolymers were optimized based on the mean droplet/particle diameter (MDD/MPD), polydispersity index (PDI) and net charge on the droplets/capsules. Prepared core-shell structures or nanocapsules, having MPD of 159.85 ± 0.92 nm, were characterized by laser diffraction (DLS), ζ-potential (ZP), atomic force microscopy (AFM), transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). Furthermore, physical stability of curcumin-loaded nanocapsules in suspension was determined and compared at different storage temperatures. This study may provide information regarding the formation of ultrasound-assisted polymeric nanocapsules from the nanoemulsion templates which could be helpful in the development of delivery systems for lipophilic food bioactives.

Stable nanoparticles prepared by heating electrostatic complexes of whey protein isolate-dextran conjugate and chondroitin sulfate.

A simple and green method was developed for preparing the stable biopolymer nanoparticles with pH and salt resistance. The method involved the macromolecular crowding Maillard process and heat-induced gelation process. The conjugates of whey protein isolate (WPI) and dextran were produced by Maillard reaction. The nanoparticles were fabricated by heating electrostatic complexes of WPI-dextran conjugate and chondroitin sulfate (ChS) above the denaturation temperature and near the isoelectric point of WPI. Then, the nanoparticles were characterized by spectrophotometry, dynamic laser scattering, zeta potential, transmission electron microscopy, atomic force microscopy, and scanning electron microscopy. Results showed that the nanoparticles were stable in the pH range from 1.0 to 8.0 and in the presence of high salt concentration of 200 mM NaCl. WPI-dextran conjugate, WPI, and ChS were assembled into the nanoparticles with dextran conjugated to WPI/ChS shell and WPI/ChS core. The repulsive steric interactions, from both dextran covalently conjugated to WPI and ChS electrostatically interacted with WPI, were the major formation mechanism of the stable nanoparticles. As a nutrient model, lutein could be effectively encapsulated into the nanoparticles. Additionally, the nanoparticles exhibited a spherical shape and homogeneous size distribution regardless of lutein loading. The results suggested that the stable nanoparticles from proteins and strong polyelectrolyte polysaccharides would be used as a promising target delivery system for hydrophobic nutrients and drugs at physiological pH and salt conditions.

Effect of enzymatic hydrolysis with subsequent mild thermal oxidation of tallow on precursor formation and sensory profiles of beef flavours assessed by partial least squares regression.

Effects of different pretreatments of tallow on flavour precursor development and flavour profiles of beef flavours (BFs) were evaluated. Analysis of free fatty acids and volatiles of tallow by GC and GC-MS indicated that the enzymatic hydrolyzed-thermally oxidized tallow formed the most characteristic flavour precursors compared with others. The results of descriptive sensory analysis confirmed that beef flavour 4 from enzymatic hydrolyzed-thermally oxidized tallow had the strongest beefy, meaty and odour characteristics, followed by beef flavour 2 from oxidized tallow. Electronic nose data confirmed the accuracy of the sensory analysis results. The correlation analysis of 51 volatile compounds in tallow and sensory attributes of BFs showed that some compounds, especially aldehydes, made a significant contribution to sensory attributes. Correlation analysis of free fatty acids and sensory attributes through partial least squares regression (PLSR) confirmed that the moderate enzymatic hydrolysis-thermal oxidation pretreatment of tallow was necessary to achieve the characteristic beef flavour.

Influence of enzymatic hydrolysis and enzyme type on the nutritional and antioxidant properties of pumpkin meal hydrolysates.

Nutritional and antioxidant properties of pumpkin meal and their hydrolysates prepared by hydrolysis with alcalase, flavourzyme, protamex or neutrase were evaluated. The hydrolysis process significantly increased protein content from 67.07% to 92.22%. All the essential amino acids met the Food and Agriculture Organization of United Nations/World Health Organization (WHO/FAO) suggested requirements for children and adults. The amino acid score (AAS) of meal was increased from 65.59 to 73.00 except for flavourzyme (62.97) and protamex (62.50). The Biological Value (BV) was increased from 53.18 to 83.44 except for protamex (40.97). However hydrolysis decreased the Essential Amino Acid/Total Amino Acid ratio (EAA/TAA) from 32.98% to 29.43%. Protein Efficiency Ratio (PER) was comparable to that of good quality protein (1.5) except for flavourzyme hydrolysate which had PER1 = 0.92, PER2 = 1.03, PER3 = 0.38. The in vitro protein digestibility (IVPD) increased from 71.32% to 77.96%. Antioxidant activity increased in a dose-dependent manner. At 10 mg mL(-1), the hydrolysates had increased 1,1-diphenyl-2-picrylhydrazy (DPPH) radical scavenging activities from 21.89% to 85.27%, the reducing power increased from Abs(700nm) 0.21 to 0.48. Metal (Iron) chelating ability was improved from 30.50% to 80.03% at 1 mg mL(-1). Hydrolysates also showed better capabilities to suppress or delay lipid peroxidation in a linoleic acid model system. Different proteases lead to different Degrees of Hydrolysis (DH), molecular weight (MW) distribution, amino acid composition and sequence, which influenced the nutritional properties and antioxidant activities of the hydrolysates. Alcalase was the most promising protease in production of pumpkin protein hydrolysates with improved nutritional quality, while flavourzyme was best in production of hydrolysates with improved antioxidative activity among various assays. These results showed that hydrolysates from by-products of pumpkin oil-processing might serve as alternative sources of dietary proteins with good nutritional quality, and protection against oxidative damage.

Contribution of beef base to aroma characteristics of beeflike process flavour assessed by descriptive sensory analysis and gas chromatography olfactometry and partial least squares regression.

Descriptive sensory analysis and gas chromatography-mass spectrometry (GC-MS) analysis were conducted to investigate changes in aroma characteristics of beeflike process flavours (BPFs) prepared from enzymatically hydrolyzed beef (beef base) of different DH (degree of hydrolysis) with other ingredients. Five attributes (beefy, meaty, simulate, mouthful and roasted) were selected to assess BPFs. The results of descriptive sensory analysis confirmed that BPF2 from beef base of moderate DH 29.13% was strongest in beefy, meaty and simulate characteristics; BPF4 and BPF5 from beef base of higher DH (40.43% and 44.22%, respectively) were superior in mouthful and roasted attributes respectively; while BPF0 without beef base gave weaker odour for all attributes. Twenty six compounds from GC-MS were selected as specific compounds to represent beef odour based on their odour-active properties assessed by a detection frequency method of GC-O and correlation of their contents with sensory attributes intensity. Correlation analysis of molecular weight (MW) of peptides, odour-active compounds and sensory attributes through partial least squares regression (PLSR) further explained that beef base with DH of 29.13% was a desirable precursor for imparting aroma characteristics of beeflike process flavour.