Investigation of the Volatile Profile of Red Jujube by Using GC-IMS, Multivariate Data Analysis, and Descriptive Sensory Analysis.

peer reviewedThe aroma characteristics of six red jujube cultivars (Jinchang-'JC', Junzao-'JZ', Huizao-'HZ', Qiyuexian-'QYX', Hetiandazao-'HTDZ', and Yuanzao-'YZ'), cultivated in Xinjiang Province, China, were studied by E-nose and GC-IMS. The presence of acetoin, E-2-hexanol, hexanal, acetic acid, and ethyl acetate played an important role in the classification results. JC, JZ, HZ, and YZ were different from others, while QYX and HTDZ were similar to each other. HZ had the most abundant specific VOCs, including linalool, nonanoic acid, methyl myristoleate, 2-acetylfuran, 1-octen-3-one, E-2-heptenal, 2-heptenone, 7-octenoic acid, and 2-pentanone. HZ had higher intensity in jujube ID, floral, sweet, and fruity attributes. Correlation analysis showed that jujube ID (identity) might be related to phenylacetaldehyde and isobutanoic acid that formed by the transamination or dehydrogenation of amino acids; meanwhile, the sweet attribute was correlated with amino acids, including threonine, glutamic acid, glycine, alanine, valine, leucine, tyrosine, phenylalanine, lysine, histidine, and arginine

Quality assessment and variety classification of seed‐used pumpkin by‐products: Potential values to deep processing

Seed-used pumpkin (SUP) is known as a traditional popular crop, which is mainly processed for seeds. However, the by-products (49 times the amount of seeds) were disposed directly into the field as waste. In this study, potential values of seed-used pumpkins’ by-products (SUPBs, peel and pulp) as food resource were investigated. Physico-chemical, nutritional, and aroma profile of ten varieties of SUPBs were characterized, and variety differences were also distinguished. Peel “a*” value, water, fructose, crude fat, sucrose, and Ca contents were the 6 characteristic indicators of SUPBs which screened through correlation analysis, principal component analysis (PCA), and PCA-X model. Comprehensive evaluation of physico-chemical, nutritional, and aroma profile, four varieties by-products (Jf8#, Nf8#, Rbf#, and Rf9#) were always characterized into Cluster Ⅰ. Other varieties were classified into Cluster Ⅱ based on aroma profile. However, two varieties by-products (Db1# and Xn1#) presented significant differences from others (Db2#, Db3#, Db4#, and Myxc2#) in physico-chemical and nutritional indices, they were classified as Cluster III and IV, respectively. Db1# had the highest nutritional value of soluble solid (11.78 ºBx), pectin (1,166.15 mg/ 100 g), total carotenoid (19.57 mg/ 100 g), and total sugar (13.69 g/ 100 g). Among all the SUPBs, Db1# had a relatively higher nutritional value, which was suitable as food resource for deep processing

Quality assessment and variety classification of seed-used pumpkin by-products: Potential values to deep processing

Seed-used pumpkin (SUP) is known as a traditional popular crop, which is mainly processed for seeds. However, the by-products (49 times the amount of seeds) were disposed directly into the field as waste. In this study, potential values of seed-used pumpkins’ by-products (SUPBs, peel and pulp) as food resource were investigated. Physico-chemical, nutritional, and aroma profile of ten varieties of SUPBs were characterized, and variety differences were also distinguished. Peel “a*” value, water, fructose, crude fat, sucrose, and Ca contents were the 6 characteristic indicators of SUPBs which screened through correlation analysis, principal component analysis (PCA), and PCA-X model. Comprehensive evaluation of physico-chemical, nutritional, and aroma profile, four varieties by-products (Jf8#, Nf8#, Rbf#, and Rf9#) were always characterized into Cluster Ⅰ. Other varieties were classified into Cluster Ⅱ based on aroma profile. However, two varieties by-products (Db1# and Xn1#) presented significant differences from others (Db2#, Db3#, Db4#, and Myxc2#) in physico-chemical and nutritional indices, they were classified as Cluster III and IV, respectively. Db1# had the highest nutritional value of soluble solid (11.78 ºBx), pectin (1,166.15 mg/ 100 g), total carotenoid (19.57 mg/ 100 g), and total sugar (13.69 g/ 100 g). Among all the SUPBs, Db1# had a relatively higher nutritional value, which was suitable as food resource for deep processing

Economic Evaluation of CCUS Retrofitting of Coal-fired Power Plants Based on Net Cash Flow

Carbon Capture, Utilization and Storage (CCUS) is one of the key technologies for realizing large-scale low-carbon utilization of coal-fired power plants in service. How to evaluate its economics is crucial to the decision-making of traditional coal-fired power enterprises. This paper analyzes the changes in the physical, emission and economic parameters of in-service coal-fired power plants without and with the CCUS retrofit. A method for evaluating the economic feasibility of coal-fired power plants retrofitting based on net cash flow is proposed, which compares the impact of CCUS retrofit on the net present value of the remaining life cycle of the power plant. The impact of uncertain parameters such as carbon dioxide sales unit price, carbon capture device operating cost, free carbon quota, and carbon emission right price on the evaluation results are analyzed

Volatile Profile Characterization of Winter Jujube from Different Regions via HS-SPME-GC/MS and GC-IMS

peer reviewedA combined untargeted and targeted approach was established for fingerprinting volatile organic compounds in winter jujubes from eight regions of China. Volatiles, including alcohols, aldehydes, acids, esters, and alkenes, were identified by gas chromatography-ion mobility spectrometry (GC-IMS). Benzyl alcohol, octanoic acid, 2-hexenal, linalool, 2-nonenal, and ethyl decanoate were the most common compounds present in all jujubes. Principal component analysis (PCA) from GC-IMS and untargeted E-nose showed that the main volatile organic compounds (VOCs) of most jujubes were similar. The volatile organic compounds of winter jujubes from Yuncheng city, Shanxi province, and Aksu region, Xinjiang province, were significantly different from those from other regions. 1-Penten-3-ol, ethyl hexanoate, methyl laurate, and 2-formyltoluene were the markers of XJAKS with green and fruity aroma, and SXYC could be labeled by acetone and 2-methoxyphenol with woody and pungent aroma. GC-IMS was an effective method for volatile fingerprinting of jujubes with high sensitivity and accuracy

Rapid and sensitive quantitation of DDMP (2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one) in baked red jujubes by HS-SPME-GC-MS/MS

peer reviewedBaked red jujube is a common food ingredient used to enrich the nutritional value and enhance the aroma. DDMP (2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one) with intense bitterness and potential toxicity may be present in several baked red jujube-based products but there are no well-defined methods to measure it quickly, sensitively, and accurately. Headspace solid-phase microextraction with gas chromatography-tandem mass spectrometry (HS-SPME-GC-MS/MS) was applied for the analysis of DDMP. The standard curve was linear between the concentrations of 0.01 and 100 μg/mL, with a limit of detection at 0.1 ng/g that below the sensory threshold of DDMP (2.06 μg/g). Five cultivars of baked red jujubes from China were evaluated with the method for DDMP content (4.55–46.50 μg/g). The results indicated that jujube cultivars with a higher molar ratio of proline to glucose, lower moisture content, and stronger ability to resist water stress should be avoided from baking to modulate the formation of DDMP

Key aroma-active compounds identification of Ziziphus jujuba cv. Huizao: Effect of pilot scale freeze-drying

peer reviewedAroma profile and key aroma-active of red jujube subjected to pilot scale freeze drying (FD) were investigated based on molecular sensory science. After FD, 41 aroma compounds were identified through gas chromatography-olfactometry-mass spectrometry (GC-O-MS) and quantified through calibration curves. The total aroma compounds content was decreased 26.71% compared with raw red jujube, of which ketones and acids contents were decreased 63.33% and 62.88%, while, the esters, lactones and alcohols contents were increased 34.10%, 8.52% and 480.17%, respectively. Through the GC-O-MS, odor active values combined with recombination and omission tests, 14 key aroma-active compounds were identification in freeze-dried red jujube. In which, 2-ethyl-3,5-dimethyl-pyrazine had the highest OAV (2687.00) and dominated the roast note of aroma profile. In addition, ethyl heptanoate, hexyl acetate, 2,3-butanediol, ethyl dodecanoate and 5-heptyloxolan-2-one were newly identified as the key aroma-active compounds in freeze-dried red jujube

Elucidation of baking induced changes in key odorants of Red Jujube (Ziziphus jujuba Mill. cv.‘Junzao’)

peer reviewedJujube is widely consumed fresh or used as ingredient in food industry, especially in China. Processed red jujube is characterized by a caramel-like and roasted aroma which contrasted with the sweet and fruity aroma of raw red jujube. The characteristic volatiles that contribute to this aroma have never been elucidated. The volatile organic components (VOCs) of baked and raw red jujubes were determined based on molecular sensory science including gas chromatography-mass spectrometry-olfactometry (GC-MS-O), aroma extract dilution analysis (AEDA), odor activity value (OAV), recombination, and omission experiments. Results revealed that 1-(2,6,6-trimethyl-1,3-cyclohexadien-1-yl)− 2-buten-1-one, 5-butyltetrahydro-2-furanone, and hexanoic acid were the common key odor active compounds in raw and baked red jujube. However, the baking process triggered the formation of aromatic hydrocarbon molecules in red jujube including 1H-pyrrole-2-carboxaldehyde (0.21 μg/g), 3,5-dihydroxy-6-methyl-2,3-dihydro-4H-pyran-4-one (34.15 μg/g), 5-methyl-2-furancarboxaldehyde (0.36 μg/g), and benzaldehyde (0.11 μg/g)

Assessment of anticaking agent on caking behavior of jujube amorphous powder via glass transition and state diagram

Jujube (Ziziphus jujuba Mill.) powder is hygroscopic and highly prone to caking during storage which could significantly reduce product quality. Anticaking agents are usually added to maintain flowability of powders and prevent caking. Caking behaviors of jujube powder and blends with anticaking agents (calcium stearate, magnesium stearate, and silicon dioxide at 1, 2, 3% w/w) as affected by temperature (25\ua0°C, 35\ua0°C, 45\ua0°C), mixing speed (22, 73, 96\ua0rpm), and mixing time (1, 5, 10, 15, 20\ua0min at 25\ua0°C) of powders exposed at 75% RH for 5\ua0h were investigated by FT4 powder rheometer. Energy of crust that formed during caking was determined. Results showed that anticaking agents resulted in significant effect on the moisture sorption and crust strength formed during caking of jujube powders. Calcium stearate (2% w/w) proved to be the most effective to improve the flowability and delay onset of powder caking with significant reduction in the crust strength of powder cake from 170 to 2\ua0mJ/g when powders exposed to 75% RH for 5\ua0h at 25\ua0°C. Mixing speed at 73\ua0rpm and mixing time of 5~20\ua0min could present better flowability of jujube powders and delay the onset of caking. Lower (22\ua0rpm) and higher (96\ua0rpm) mixing speeds and higher temperatures (45\ua0°C) could speed up caking rate in powder blends. State diagrams established based on moisture sorption isotherm and glass transition curves showed that jujube powders with and without calcium stearate addition were stable at 25\ua0°C when water content was lower than 0.095 and 0.088\ua0g water/g sample, respectively

Comprehensive investigation on free and glycosidically bound volatile compounds in Ziziphus jujube cv. Huizao

peer reviewedBoth free and glycosidically bound volatile compounds of Ziziphus jujube cv. Huizao were comprehensively investigated in this study. There were 43 and 17 volatile compounds identified in free and bound fraction of “Huizao”, respectively. Green, sweet, floral, fruity, cream, sour/rancid and nut notes could describe the aroma profiles through quantitative descriptive analysis. In terms of free volatiles, 22 compounds with odor activity values ≥ 1 and 21 compounds with detection frequency ≥ 2. 3-Hydroxy-2-butanone, butane-2,3-dione, methyl decanoate, ethyl decanoate, methyl dodecanoate, 5-propyloxolan-2-one, 5-butyloxolan-2-one, 2-ethyl-3,5- dimethyl-pyrazine, (E)-but-2-enoic acid, hexanoic acid, hexanal, 6-methyl-5-hepten-2-one, 3-oxobutan-2-yl acetate, 5-ethyloxolan-2-one, and 3-methyl-butanoic acid were identified as key aroma-active compounds in “Huizao” via recombination and omission tests. Moreover, key aroma-active compounds of 3-hydroxy-2-butanone, 5-ethyloxolan-2-one, (E)-but-2-enoic acid, hexanoic acid and 3-methyl-butanoic acid were also detected in bound fraction, aroma intensity of “Huizao” could be effectively enhanced by enzymatic hydrolysis