Cooking surface temperatures, steak thickness, and quality grade effects on volatile aroma compounds

Beef flavor attributes were evaluated in USDA TopChoice and Select beef top loin steaks cut 1.3 cm (THIN) or 3.8 cm (THICK) andcooked on a commercial flat top grill at 177˚C (LOW) or 232˚C (HIGH) grillsurface temperature. Gas chromatography/mass spectrophotometry, was used toevaluate volatile aroma compounds.  USDASelect steaks had more 2-octene and less trimethyl pyrazine in (P<0.05) THINsteaks than THICK steaks, while Choice was unaffected by steak thickness(P>0.05).  Benzene acetaldehyde washigher and 4-hydroxybenzoic acid was higher in Select LOW grill temperaturescompared to Select HIGH grill temperatures, while 5-methyl-2-furancarboxaldehyde was only present in Choice HIGH grill temperatures (P<0.05).Two acid, three alcohol, one aldehyde, one alkane, and one ketone volatilearoma compounds were higher (P<0.05) for LOW compared to HIGH.  Conversely, five alcohols, two aldehyde, twoalkane, all four furans, six ketones, four pyrazines, along with 1H-indole, twopyrroles, two pyridines, and one benzene aroma compounds were higher (P<0.05)in HIGH compared to LOW.  Additionally,one alcohol, two aldehydes, one ketones, one sulfur-containing, and six othervolatile compounds were lower, while one acid, one alcohol, one aldehyde, twofurans, one ketone, three pyrazine, one sulfur-containing, and one othervolatile compounds were higher in the THIN compared to THICK.  Some aroma compounds like 2-butanone,4-methyl-2-pentanone, 1-ethyl-1H-pyrrole, 1-methyl-1H-pyrrole, and2-methyl-pyridine were only present in THICK cooked HIGH (P<0.05). Steakthickness and grill time are important factors to consider in the developmentof positive Maillard reaction products.@font-face{font-family:"Cambria Math";panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:roman;mso-font-pitch:variable;mso-font-signature:-536870145 1107305727 0 0 415 0;}@font-face{font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;mso-font-charset:0;mso-generic-font-family:swiss;mso-font-pitch:variable;mso-font-signature:-536859905 -1073732485 9 0 511 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin:0in;margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:12.0pt;font-family:"Calibri",sans-serif;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-family:"Calibri",sans-serif;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;}div.WordSection1{page:WordSection1;}@font-face{font-family:"MS Mincho";panose-1:2 2 6 9 4 2 5 8 3 4;mso-font-alt:"ＭＳ 明朝";mso-font-charset:128;mso-generic-font-family:modern;mso-font-pitch:fixed;mso-font-signature:-536870145 1791491579 134217746 0 131231 0;}@font-face{font-family:"Cambria Math";panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:roman;mso-font-pitch:variable;mso-font-signature:-536870145 1107305727 0 0 415 0;}@font-face{font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;mso-font-charset:0;mso-generic-font-family:swiss;mso-font-pitch:variable;mso-font-signature:-536859905 -1073732485 9 0 511 0;}@font-face{font-family:Cambria;panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:roman;mso-font-pitch:variable;mso-font-signature:-536870145 1073743103 0 0 415 0;}@font-face{font-family:"\@MS Mincho";panose-1:2 2 6 9 4 2 5 8 3 4;mso-font-charset:128;mso-generic-font-family:modern;mso-font-pitch:fixed;mso-font-signature:-536870145 1791491579 134217746 0 131231 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin:0in;margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:12.0pt;font-family:"Cambria",serif;mso-ascii-font-family:Cambria;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"MS Mincho";mso-fareast-theme-font:minor-fareast;mso-hansi-font-family:Cambria;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;}p.Major, li.Major, div.Major{mso-style-name:Major;mso-style-unhide:no;mso-style-qformat:yes;margin:0in;margin-bottom:.0001pt;text-align:center;line-height:200%;mso-pagination:widow-orphan;font-size:14.0pt;mso-bidi-font-size:12.0pt;font-family:"Times New Roman",serif;mso-fareast-font-family:"MS Mincho";mso-fareast-theme-font:minor-fareast;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-family:"Cambria",serif;mso-ascii-font-family:Cambria;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"MS Mincho";mso-fareast-theme-font:minor-fareast;mso-hansi-font-family:Cambria;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;}div.WordSection1{page:WordSection1;}

Digital Smoke Taint Detection in Pinot Grigio Wines Using an E-Nose and Machine Learning Algorithms Following Treatment with Activated Carbon and a Cleaving Enzyme

The incidence and intensity of bushfires is increasing due to climate change, resulting in a greater risk of smoke taint development in wine. In this study, smoke-tainted and non-smoke-tainted wines were subjected to treatments using activated carbon with/without the addition of a cleaving enzyme treatment to hydrolyze glycoconjugates. Chemical measurements and volatile aroma compounds were assessed for each treatment, with the two smoke taint amelioration treatments exhibiting lower mean values for volatile aroma compounds exhibiting positive ‘fruit’ aromas. Furthermore, a low-cost electronic nose (e-nose) was used to assess the wines. A machine learning model based on artificial neural networks (ANN) was developed using the e-nose outputs from the unsmoked control wine, unsmoked wine with activated carbon treatment, unsmoked wine with a cleaving enzyme plus activated carbon treatment, and smoke-tainted control wine samples as inputs to classify the wines according to the smoke taint amelioration treatment. The model displayed a high overall accuracy of 98% in classifying the e-nose readings, illustrating it may be a rapid, cost-effective tool for winemakers to assess the effectiveness of smoke taint amelioration treatment by activated carbon with/without the use of a cleaving enzyme. Furthermore, the use of a cleaving enzyme coupled with activated carbon was found to be effective in ameliorating smoke taint in wine and may help delay the resurgence of smoke aromas in wine following the aging and hydrolysis of glycoconjugates.

Transcriptome and metabolite profiling analyses provide insight into volatile compounds of the apple cultivar ‘Ruixue’ and its parents during fruit development

Background Aroma is one the most crucial inherent quality attributes of fruit. ‘Ruixue’ apples were selected from a cross between ‘Pink Lady’ and ‘Fuji’, a later ripening yellow new cultivar. However, there is little known about the content and composition of aroma compounds in ‘Ruixue’ apples or the genetic characters of ‘Ruixue’ and its parents. In addition, the metabolic pathways for biosynthesis of aroma volatiles and aroma-related genes remain poorly understood. Results Volatile aroma compounds were putatively identified using gas chromatography-mass spectrometry (GC–MS). Our results show that the profile of volatile compounds changes with ripening. Aldehydes were the dominant volatile compounds in early fruit development, with alcohols and esters increasing dramatically during maturation. On the basis of a heatmap dendrogram, these aroma compounds clustered into seven groups. In ripe fruit, esters and terpenoids were the main aroma volatiles in ripening fruit of ‘Pink Lady’ and ‘Fuji’ apples, and they included butyl 2-methylbutanoate; propanoic acid, hexyl ester; propanoic acid, hexyl ester; hexanoic acid, hexyl ester; acetic acid, hexyl ester and (Z, E)-α-farnesene. Interestingly, aldehydes and terpenoids were the dominant volatile aroma compounds in ripening fruit of ‘Ruixue’, and they mainly included hexanal; 2-hexenal; octanal; (E)-2-octenal; nonanal and (Z, E)-α-farnesene. By comparing the transcriptome profiles of ‘Ruixue’ and its parents fruits during development, we identified a large number of aroma-related genes related to the fatty acid, isoleucine and sesquiterpenoid metabolism pathways and transcription factors that may volatile regulate biosynthesis. Conclusions Our initial study facilitates a better understanding of the volatile compounds that affect fruit flavour as well as the mechanisms underlying differences in flavour between ‘Ruixue’ and its parents.

The Occurrence of Glycosylated Aroma Precursors in Vitis vinifera Fruit and Humulus lupulus Hop Cones and Their Roles in Wine and Beer Volatile Aroma Production

Volatile aroma compounds found in grapes and hops may be present as both free volatiles and bound glycosides. Glycosides found in the raw materials are transferred to their respective fermented beverages during production where the odorless compounds may act as a reservoir of free volatiles that may be perceived by the consumer if hydrolyzed. A review of the literature on grape and wine glycosides and the emerging literature for glycosides in hops is presented in order to demonstrate the depth of history in grape glycoside research and may help direct new research on hop glycosides. Focus is brought to the presence of glycosides in the raw materials, the effect that winemaking and brewing have on glycoside levels, and current methods for the analysis of glycosidically linked aroma compounds.