Stale Flavor Research Articles

Flowering in aged white tea: Recovering umami taste and amplifying of stale aroma

Throughout the natural aging process from new to aged white tea, the flavor evolves into a ‘stale flavor’, despite the initial umami diminishes. The flowering process, inoculation of Eurotium cristatum to white tea, improves the flavor. The impact on sensory qualities and underlying chemical basis of flowering in aged white tea warrant investigation. Sensory analysis, non-targeted metabolomics and volatilomics together deciphered flavor modifications of flowering in aged white tea from different aging years (FAWTs). Findings indicate the flowering process can recover the umami of aged white tea, enhancing the ‘stale flavor’. These changes primarily stem from oxidations of catechins and free amino acids, enrichments of flavonols and soluble sugars, and 16 pivotal aroma compounds from degradations of lipids and glycosides. Additionally, 15 volatile and 39 non-volatile compounds were identified as potential biomarkers for FAWTs. These findings offer a viable strategy to improving the quality of aged white tea.

The flavor characteristics and antioxidant capability of aged Jinhua white tea and the mechanisms of its dynamic evolution during long-term aging

This study explored the sensory characteristics, metabolites and antioxidant capability of aged Jinhua white tea (AJWT) over different years of aging and revealed the transformation mechanism of these characteristics during the long-term aging process. The flavor wheel of AJWT was constructed, and its unique flavor was dominated by mellowness, smoothness, a fungus fragrance, and a stale flavor. The high content of theabrownine, soluble sugar, flavonoids and 25 aroma components made important contributions to the formation of the unique flavor of the AJWT, and their content significantly increased during the long-term aging process of 5–10 years. This was related to the microbial bioconversion, the oxidative degradation of catechins, the hydrolysis of flavonosides and the decomposition of polysaccharides. Contrary to folk experience, AJWT had weak comprehensive antioxidant capacity, mainly due to its low content of tea polyphenols, catechin components and caffeine, which decreased significantly during the long-term aging of 5–10 years.

How maturation time affects the chemical and sensory profile of pale lager beer

The maturation of beer is an important production step with an impact on its quality. Changes in the chemical and sensory profile between 2 and 6 weeks of cold maturation were evaluated in pilot brews (200 l) of a pale lager of 11% and 15% original gravity. In addition to the basic analytical parameters and shelf life, volatiles, hop essential oils, fatty acids, amino acids and stale flavour aldehydes were monitored. The sensory quality of the beers was evaluated using descriptive method. The dynamics of changes in the monitored groups of analytes during maturation of the tested variants was different, but without substantial influence on the overall impression and shelf life of the beer. Under the experimental conditions, it was possible to reduce the maturation time of a common Czech-style lager to 2 weeks of cold lagering. The gradual slight improvement in the overall impression of beers brewed at original gravity indicates the need for a long maturation period to fine-tune the sensory profile of premium lagers. A short maturation period of 2 weeks appears to be beneficial for beers brewed using a high gravity brewing protocol. The findings obtained can be a useful guide for optimising the maturation of Czech-style lager in practice, although the dynamics of changes in the monitored substances and their influence on the sensory characteristics of the beer may be to some degree different when scaled up to operational practice.

Exploring the mysterious effect of piling fermentation on Pu-erh tea quality formation: Microbial action and moist-heat action

Moist-heat action and microbial action are essential to the formation of Pu-erh tea’s quality. To explore the impact of piling fermentation (PF) environment on Pu-erh tea quality, samples subjected to spontaneous PF (SPPF) and sterile PF (STPF) from the same batch of raw material were processed, and their sensory quality and metabolic profile dynamics were determined. Sensory evaluation indicated that infusions of the SPPF samples were mainly brownish-red, stale-mellow taste, and stale aroma, whereas infusions of the STPF samples were mainly orange-red, sweet-mellow taste, and woody aroma. Metabolomics analysis identified 465 key metabolites, including 33 microbial markers and 39 moist-heat activity markers. Enzyme and pathway analyses revealed that the production of microbial enzymes accelerates the degradation of flavonoids, flavonols, and lipids and also indicated an exclusive influence of microorganisms on the lipid metabolite pathway. This study elucidated the mechanism underlying the formation of Pu-erh tea’s stale flavour.

Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) and odor activity value (OAV) to reveal the flavor characteristics of ripened Pu-erh tea by co-fermentation.

Pu-erh tea is a geographical indication product of China. The characteristic flavor compounds produced during the fermentation of ripened Pu-erh tea have an important impact on its quality. Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) and odor activity value (OAV) is used for flavor analysis. A total of 135 volatile compounds were annotated, of which the highest content was alcohols (54.26%), followed by esters (16.73%), and methoxybenzenes (12.69%). Alcohols in ripened Pu-erh tea mainly contribute flower and fruit sweet flavors, while methoxybenzenes mainly contribute musty and stale flavors. The ripened Pu-erh tea fermented by Saccharomyces: Rhizopus: Aspergillus niger mixed in the ratio of 1:1:1 presented the remarkable flavor characteristics of flower and fruit sweet flavor, and having better coordination with musty and stale flavor. This study demonstrated the content changes of ripened Pu-erh tea's flavor compounds in the fermentation process, and revealed the optimal fermentation time. This will be helpful to further understand the formation mechanism of the characteristic flavor of ripened Pu-erh tea and guide the optimization of the fermentation process of ripened Pu-erh tea.

The Effect of Mash-In Temperature on the Characteristics and Flavor Stability of Pilsner-Type Beer

Beers were brewed at mash-in temperatures of 35 °C, 50 °C, and 65 °C, and their flavor profiles and stability were examined. Beers with mash-ins at 35 °C and 50 °C exhibited full-bodied taste and estery sensory qualities with higher concentrations of esters and amino acids. Higher extract yields were obtained in wort with mash-ins at 35 °C and 50 °C, the optimal temperatures for enzymes to break down the tissue where starch granules are located. In contrast, the beer with a 65 °C mash-in temperature had a light taste and a toast-like aroma. In terms of providing nutrition for the yeast, the proteolytic process to produce amino acids seemed unnecessary for brewing beer made exclusively from malt. Following a month of storage at 30 °C, cardboard flavors predominated in beers with mash-in temperatures of 35 °C and 50 °C, while honey and sherry-like scents predominated in beers with a mash-in temperature of 65 °C. The concentrations of the 14 components contributing to the stale flavor of Pilsner-type beers, including Strecker aldehydes, did not correlate with mash-in temperature, with the exception of the concentration of (E)-2-nonenal, even though the mash-in temperatures were predicted to affect the formation of Strecker aldehydes during beer storage.

Research on Tea Branding Based on the Consumer Perspective—Taking Liubao Tea as an Example

This paper is based on the consumer perspective, on the basis of field research and questionnaire survey to obtain first-hand data, first of all, the use of hierarchical analysis, logistic regression analysis and other data analysis methods to study the current constraints on further brand building of Liubao tea. And based on the above-mentioned influencing factors, the corresponding solution strategies are proposed. The study concluded that marketing transformation, cultural heritage, network publicity and villagers' participation have greater constraints on further brand building; it was found that the taste and stale flavor of Liubao tea are the main factors causing poor consumer reviews of Liubao tea.

Evolution of sensory analysis attributes and volatile aging markers in bottle fermented craft beers during storage at different temperatures.

Beer oxidation is strictly linked to its shelf life. Chemical variation in aldehydes, higher alcohols, hops bitter substances and esters, also could have a role key in stale flavor. Bottle refermentation, is the method by which beer in the bottle is made sparkling and is often used in craft brewing. Before the process an amount of oxygen in the headspace can be a potential source of oxidation. We investigated the effect of oxygen and temperature during storage of refermented craft beer in bottles with standard and oxygen scavenger caps. Beer was stored for 13 weeks at 6, 22 and 45 °C for forced aging, and monitored by technological analysis, SPME (-) and - MS (-), Electron Paramagnetic Resonance (EPR). At 45 °C, the samples showed a decrease of International Bitterness Units and an increase in color and concentrations of oxidized molecules, and other related with the high temperature (aldehydes and furanic compounds respectively). No differences were observed between samples stored at 6 and 22 °C. Sensory analysis showed differences in the perception of paint, sweet, cardboard and freshness attributes in the samples stored at 45 °C. No differences were observed in the use of standard and oxygen scavenger caps.

How are the sensory properties perceived by consumers? A case study with pressurized tropical mixed juice

Tropical fruits, such as cashew apple, acerola, and melon, can be used to obtain innovative juices with high contents of bioactive compounds. Technological processes are needed to ensure the safety of products during their shelf life. However, these processes can modify the sensory properties of the juice, which have an important role in consumer acceptance. From this perspective, this study aimed to evaluate consumer perception of the sensory characteristics of tropical mixed juice based on cashew apple, acerola, and melon obtained using different processing methods during cold storage at 4° C. Microbiological aspects were monitored during refrigerated storage at 4 °C. Samples were exposed to four technological processes: control (unprocessed), pasteurization (90 °C/1 min), and high-pressure processing: HHP1 (500 MPa/5 min) and HHP2 (520 MPa/2 min). Thirty fruit juice consumers participated in the characterization of mixed juices using rate-all-that-apply (RATA) questions. Samples were analyzed at zero, 14, and 28 days of storage at 4 °C. Data were analyzed by ANOVA, and Fisher's test was used for post-hoc comparison of means and PCA. Results showed that 12 of the 22 RATA terms differed (p ≤ 0.05) regarding the mean perceived intensity, suggesting that consumers perceived differences in the sensory characteristics of the juices. The first dimension of the PCA separated the pasteurized juices from the others. Pasteurized samples were characterized by yellow color, cooked aroma, cooked flavor, off aroma, off flavor, stale aroma, and stale flavor. On the other hand, the unprocessed (control) and pressurized (HPP1 and HPP2) juices were characterized by orange color, fruit aroma, fruit flavor, sweet aroma, fresh juice, and watery consistency. Results confirmed the suitability of the sensory characterization performed by consumers using RATA and the potential of HHP to obtain juices with sensory characteristics similar to the fresh product.

Effect of inoculation with Penicillium chrysogenum on chemical components and fungal communities in fermentation of Pu-erh tea

Developing an effective method to improve the quality of Pu-erh tea is of great scientific and commercial interest. In this work, Penicillium chrysogenum P1 isolated from Pu-erh tea was inoculated in sterilized or unsterilized sun-dreid green tea leaves to develop pure-culture fermentation (PF) and enhanced fermentation (EF) of Pu-erh tea. Spectrophotometry and high performance liquid chromatography determined that contents of free amino acids (FAA), total tea polyphenols and eight polyphenolic compounds in PF were significantly lower than these in non-inoculation control test (CK) (P < 0.05), whereas the contents of soluble sugars and theabrownins (TB) in PF were significantly higher (P < 0.05) than in CK. A total of 416 volatile compounds were detected by headspace solid-phase micro-extraction combined with gas chromatography-mass spectrometry. Comparison to CK, 124 compounds in PF were degraded or decreased significantly [Variable importance in projection [(VIP) > 1.0, P < 0.05, fold change (FC) < 0.5], whereas 110 compounds in PF were formed or increased significantly (VIP > 1.0, P < 0.05, FC > 2). Compared with normal fermentation (NF), the levels of gallic acid, (+)-catechin, (−)-epicatechin and 64 volatile compounds in EF were significantly lower (VIP > 1.0, P < 0.05, FC < 0.5), whereas the levels of FAA and 39 volatile compounds were significantly higher (VIP > 1.0, P < 0.05, FC > 2). Amplicon sequencing of fungal internal transcribed spacer 1 (ITS1) revealed that P. chrysogenum P1 didn’t become the dominant fungus in EF; while the fungal communities in EF were different from those in NF, in that the relative abundances of Blastobotrys bambusae and P. chrysogenum in EF were higher, and the relative abundances of Aspergillus niger and Kluyveromyces marxianus in EF were lower. Overall, inoculation of P. chrysogenum in unsterilized sun-dreid green tea leaves changed the the fungal communities in fermentation of Pu-erh tea, and chemical compounds in fermented tea leaves, i.e., the levels of TB and the compounds responsible for the stale flavor, e.g., 2-amino-4-methoxybenzothiazole were increased, resulting in improvement of the sensory quality, including mellower taste and stronger stale flavor.

Novel cis-acting regulatory elements in wild Oryza species impart improved rice bran quality by lowering the expression of phospholipase D alpha1 enzyme (OsPLDα1).

Rice bran oil is good quality edible oil, rich in antioxidants and comprised typically of oleic-linoleic type fatty acids. However, presence of a highly lipolytic enzyme Phospholipase D alpha1 (OsPLDα1) increases free fatty acid content in the oil which further leads to stale flavor and rancidity of the oil, making it unfit for human consumption. In this study, we compared the upstream regions of OsPLDα1 orthologs across 34 accessions representing 5 wild Oryza species and 8 cultivars, to uncover sequence variations and identify cis-elements involved in differential transcription of orthologs. Alignment of the upstream sequences to the Nipponbare OsPLDα1 reference sequence revealed the presence of 39 SNPs. Phylogenetic analysis showed that all the selected cultivars and wild species accessions are closely related to the reference except for three accessions of O. rufipogon (IRGC89224, IRGC104425, and IRGC105902). Furthermore, using exon-specific qRT-PCR, OsPLDα1 expression patterns in immature grains indicated significant differences in transcript abundance between the wild species accessions. In comparison to the control, lowest gene expression was observed in IRGC89224 accession (0.20-fold) followed by IRGC105902 (0.26-fold) and IRGC104425 (0.41-fold) accessions. In-silico analysis of the OsPLDα1 promoter revealed that the copy number variations of CGCGBOXAT, GT1CONSENSUS, IBOXCORE, NODCON2GM, OSE2ROOTNODULE, SURECOREATSULTR11, and SORLIP1AT cis-elements play an important role in the transcriptional activities of orthologous genes. Owing to the presence of ARFAT and SEBF elements only in the IRGC89224 accession, which had the lowest gene expression as well, these putative upstream regulatory sequences have been identified as novel cis-elements which may act as repressors in regulating the OsPLDα1 gene expression. The accessions identified with low OsPLDα1 expressions could be further deployed as potential donors of ideal OsPLDα1 allele for transfer of the desired trait into elite rice cultivars.

Characterization of Seed Longevity and Stale Flavor of Lipoxygenase-3 Null Rice Line under High Temperature Storage

Characterization of Seed Longevity and Stale Flavor of Lipoxygenase-3 Null Rice Line under High Temperature Storage

The usage of a reflectometric method for 5-(hydroxymethyl)furan-2-carbaldehyde determination as a stale flavor sensor for beer

Abstract A rapid, mobile and objective method for in situ determination of a degree of sensory deterioration of beer caused by the aging process during storage was developed and validated. The novel method uses current reflectometric method of 5-(hydroxymethyl)furan-2-carbaldehyde (HMF) determination for the purpose of taste sensor. It requires only few minutes and an easy-to-use mobile reflectometer with test strips. According to our previous study, HMF is a very good indicator of a stale flavor in beer determined by a sensory analysis (correlation higher than 0.96). The reflectometric signal is transformed to the degree of the stale flavor using specified algorithm, which was derived in this study. The method provides results comparable with the sensory analysis by a trained sensory panel for lager beers and also provides objective reflection of beer deterioration for other beer styles.

Lactobacillus casei starter culture improves vitamin content, increases acidity and decreases nitrite concentration during sauerkraut fermentation

SummaryTo investigate the effects of Lactobacillus casei on Chinese sauerkraut fermentation, L. casei 11MZ‐5‐1 was inoculated into Chinese sauerkraut. Physicochemical indexes were measured, and the microbial dynamics during the fermentation were analysed by quantitative real‐time PCR (qRT‐PCR) and polymerase chain reaction‐denaturing gradient gel electrophoresis (PCR‐DGGE). The result showed that inoculation with L. casei 11MZ‐5‐1 lowered the pH of the fermentation system more rapidly than in the control model (CK). The content of vitamin C (VC) (44.64 ± 2.12 mg kg−1) was higher and nitrite (under 0.76 mg kg−1) was lower than CK (P &lt; 0.05). The numbers of 16S rRNA gene copies in the experimental model (BA) were lower than in CK at the end fermentation time. According to the PCR‐DGGE analyses, 22 and 17 specific bands were detected in CK and BA, respectively. L. paracasei and L. casei were predominant during the fermentation in BA. The relative abundance and diversity indices of bacteria in BA were 8.23 ± 0.25 and 2.01 ± 0.06, respectively, lower than in the CK (P &lt; 0.05). So, the L. casei 11MZ‐5‐1 inoculations could effectively inhibit the microbial diversity in the fermentation system. The fermented cabbage with L. casei 11MZ‐5‐1 was more favourably estimated by consumers in terms of colour, crispness, sourness, aroma, bitterness, stink, stale flavour and overall acceptability.

Protein Oxidation and Sensory Quality of Brine-Injected Pork Loins Added Ascorbate or Extracts of Green Tea or Maté during Chill-Storage in High-Oxygen Modified Atmosphere.

Background: Ascorbate is often applied to enhance stability and robustness of brine-injected pork chops sold for retail, but may affect protein oxidation, while plant extracts are potential substitutes. Methods: Brine-injected pork chops (weight-gain ~12%, NaCl ~0.9%) prepared with ascorbate (225 ppm), green tea extract (25 ppm gallic acid equivalents (GAE)), or maté extract (25 ppm GAE) stored (5 °C, seven days) in high-oxygen atmosphere packaging (MAP: 80% O2 and 20% CO2) were analyzed for color changes, sensory quality, and protein oxidation compared to a control without antioxidant. Results: No significant differences were observed for green tea and maté extracts as compared to ascorbate when evaluated based on lipid oxidation derived off-flavors, except for stale flavor, which maté significantly reduced. All treatments increased the level of the protein oxidation product, α-aminoadipic semialdehyde as compared to the control, and ascorbate was further found to increase thiol loss and protein cross-linking, with a concomitant decrease in the sensory perceived tenderness. Conclusions: Green tea and maté were found to equally protect against lipid oxidation derived off-flavors, and maté showed less prooxidative activity towards proteins as compared to ascorbate, resulting in more tender meat. Maté is a valuable substitute for ascorbate in brine-injected pork chops.

Temperature and light conditions at different latitudes affect sensory quality of broccoli florets (Brassica oleracea L. var. italica).

Broccoli (Brassica oleracea L. var. italica) is a popular vegetable grown at a wide range of latitudes. Plants were grown in 2009-2011 in pots with standardized soil, irrigation and nutrient supply under natural temperature and light conditions at four locations (42-70° N). A descriptive sensory analysis of broccoli florets was performed by a trained panel to examine any differences along the latitudinal gradient for 30 attributes within appearance, odour, taste/flavour and texture. Average results over three summer seasons in Germany, southern Norway and northern Norway showed that the northernmost location with low temperatures and long days had highest scores for bud coarseness and uniform colour, while broccoli from the German location, with high temperatures and shorter days, had highest intensity of colour hue, whiteness, bitter taste, cabbage flavour, stale flavour and watery flavour. Results from two autumn seasons at the fourth location (42° N, Spain), with low temperatures and short days, tended toward results from the two northernmost locations, with an exception for most texture attributes. Results clearly demonstrate that temperature and light conditions related to latitude and season affect the sensory quality of broccoli florets. Results may be used in marketing special quality regional or seasonal products. © 2016 Society of Chemical Industry.

Optimization of kilning progress for equilibrating multiple parameters that strictly affect malt flavour and sensory evaluation

This study developed a multiple-parameter equilibration-based kilning technology optimization method with a Box–Behnken factorial design and response surface methodology, assessing 10 kinds of indexes from multiple perspectives, including malt stale flavour, malty aroma and sensory evaluation, simultaneously. The results indicated that lipoxygenase (LOX) activity, nonenal potential and sensory score had a tendency to decline, while 4-hydroxy-2,5-dimethyl-3 (2H)-furanone, thiobarbituric acid (TBZ) and stale aldehydes increased with the rise in kilning temperature, the extension of kilning time and withering time. The corresponding second-order mathematical models were established for predicting each parameter. Among them, p-values of a model equation of LOX activity, nonenal potential, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, TBZ, methional and furfural were all 0.9, which indicated that these equations had higher significance and that data in excess of 90% could be explained. Subsequently, the numerical optimization of kilning technology was carried out for balancing these positive or negative parameters and the optimum kilning temperature, kilning time and withering time were found to be 86.35 °C, 3.19 h and 14.00 h, respectively. Compared with the values of the original response, the values of the 10 parameters were optimized from 2.2 to 65.2%. This method offers an ability to monitor malt characteristics to obtain higher quality malt. Further, the method will help maltsters and brewers to comprehensively understand malt with different cultivar genetics and growing environments. Copyright © 2016 The Institute of Brewing & Distilling

Analysis of Volatile Odor Components of Superheated Steam-cooked Rice with a Less Stale Flavor

Milled common Japonica rice was cooked using a newly developed superheated steam rice cooking machine and the volatile odor compounds of the steamed rice and of the steam generated during cooking were analyzed. At least 22 odorous compounds were found in the steam by GC-olfactometry, of which 13 were identified by GC-MS. Hexanal and (E,E)-2,4-decadienal, which are known odor compounds characteristic of cooked rice, were identified, and four compounds, including longifolene and 2-methoxyphenol, were newly identified in Japonica rice. The amounts of hexanal and (E,E)-2,4-decadienal in steamed rice, extracted with methyl tert-butyl ether, were essentially the same as in ordinary cooked rice. On the other hand, headspace analysis showed that the levels of odor compounds in steamed rice were less than 10% that of ordinary cooked rice. Only small amounts of odorants appear to be released from the surfaces of steamed rice grains.

Marker-assisted breeding of a LOX-3-null rice line with improved storability and resistance to preharvest sprouting

Breakage of the tight linkage between rice seed lipoxygenase - 3 and easy preharvest sprouting trait led to breeding of lines with few stale flavors after long storage and desirable preharvest sprouting resistance. Lipoxygenase-3 (LOX-3) is involved in the production of volatile constituents in stored rice, and the development of stale flavor is delayed in LOX-3 null rice. In the process of breeding new LOX-3-null lines with long storability, we found a close association between LOX-3 and preharvest sprouting resistance. To determine whether this relationship was due to the tight linkage of two genes or the pleiotropic effect of LOX-3, we performed marker-assisted selection using a BC3F3 population derived from crosses between LOX-3-present/preharvest sprouting-resistant lines and LOX-3-null/preharvest susceptible lines. In one individual, a recombination event occurred 13 kb downstream of LOX-3 (RM15750) and a significant quantitative trait locus, namely qPHS3, for easy preharvest sprouting trait (LOD = 10.4) was detected in an 842-kb region between RM15711 and RM15768. Using BC3F4 and BC3F5 populations, we succeeded in selecting LOX-3-absent and preharvest sprouting-resistant lines with only a 393-kb introgressed chromosome segment from the donor line for LOX-3-null at the LOX-3 locus on chromosome 3. This result indicated that the LOX-3 gene and the locus affecting preharvest sprouting are distinct. The selected line was named 'Hokuriku 244'. Sensory testing of rice grains with and without LOX-3 confirmed that stale flavor production in LOX-3-null rice during storage was lower than in normal LOX-3 rice. These results indicated that rice varieties with little stale flavor after long storage and preharvest sprouting resistance had been selected.

Storage-induced changes in the sensory characteristics and volatiles of conventional and lactose-hydrolyzed UHT processed milk

Storage-induced changes are known to be more prominent in lactose-hydrolyzed (LH) milk compared to conventional milk. Therefore the present study aimed at identifying off-flavors resembling from formation of volatiles during storage of ultra-high temperature treated (UHT) LH milk and conventional UHT milk. Further, the influence of heat processing, indirect or direct, on UHT LH milk was also examined. Storage-induced changes in sensory attributes, volatiles and primary amines were investigated during a 4 months period. Conventional UHT milk (with 5 % lactose) processed using indirect heat treatment (CONVI) and two types of UHT LH milk (with less than 0.01 % lactose) produced using either direct heat treatment (LHD) or indirect heat treatment (LHI) were represented in the study. Sensory descriptive analysis showed that fresh samples of CONVI, LHI and LHD differed in sensory properties and the samples could be differentiated according to boiled and stale aroma as well as color saturation. Differentiation of the fresh samples based on the volatile gas chromatography–mass spectrometry profile was not achievable. During storage, samples developed differently with respect to sensory characteristics, volatiles and the amount of primary amines. Partial least squares models (PLS1) including only methyl ketones and aldehydes showed that 2-butanone, 2-pentanone, 2-heptanone, 2-nonanone, heptanal, octanal and nonanal predicted stale flavor. Bitter taste, on the other hand, correlated with the amount of primary amines (Pearson’s correlation, r 2 = 0.71). This finding indicates that storage-induced changes in sensory characteristics, volatiles and primary amines depend on both differences in lactose content and the applied heat processing.