Relationships between the gross,non-volatile and volatile compositions and the sensory attributes of eight hard-type cheeses

Relationships between individual flavour attributes of eight hard-type cheeses and their volatile compounds, free amino acids (FAA), free fatty acids (FFA) and gross compositional constituents were determined. Relationships were also determined between individual texture attributes and gross compositional constituents. A trained panel of 15 assessors described the sensory characteristics of the cheeses using eight odour, twenty flavour, four appearance and nine texture attributes. Volatile compounds were isolated using a model-mouth device. FAA, FFA and gross compositional constituents were determined using standard methods. Relationships were determined by using partial least squares regression coupled with a new jack-knife method for identification and elimination of non-contributing variables. Eight flavour attributes were found to be correlated with subsets of volatile compounds, FAA, FFA and gross compositional constituents. For instance, the “nutty” flavour of Emmental was found to be positively correlated with the concentrations of propionic acid, ethyl acetate and 2-pentanone. “Nutty” flavour was negatively correlated with the concentrations of salt in moisture and pH 4.6-soluble nitrogen (pH 4.6-SN). Four texture attributes were correlated with subsets of gross compositional constituents. For example, “firmness” was positively correlated with concentrations of protein, calcium and phosphorous and negatively correlated with pH value and level of pH 4.6-SN.     

Swiss-type and Swiss–Cheddar hybrid-type cheeses: effects of manufacture on sensory character and relationships between the sensory attributes and volatile compounds and gross compositional constituents

The effects of manufacturing steps, including rate of acidification in the vat, hot room step, curd wash and ripening temperature, on the sensory character of Swiss-type and Swiss–Cheddar hybrid-type cheeses were determined. In addition, relationships were determined between sensory attributes of cheeses and their gross compositional constituents and volatile compounds. Ten assessors described the sensory characteristics using 12 odour, 19 flavour, four appearance and nine texture attributes. Gross compositional constituents were determined using standard methods. Volatile compounds were isolated using a model mouth apparatus that included a mastication device. Statistical methods were used to reduce the original sensory vocabulary to four odour, eight flavour, three appearance and five texture attributes. Results of a principal component analysis on the sensory data showed clear differences in sensory character between cheese types. For example, the Swiss-type with a low rate of acid production in the vat and a hot room step had a more 'nutty' and 'sweet' flavour than the modified Swiss-type with higher acid production and no hot room step. However, the modified Swiss–Cheddar hybrid with a curd wash step, a higher acid production and no hot room step also had a 'nutty' and 'sweet' flavour. Ripening temperature also has an effect on sensory character. Relationships between sensory character and volatile compounds and/or gross compositional constituents were determined by using partial least squares regression. One odour and one flavour attribute were shown to be correlated with subsets of volatile compounds and gross compositional constituents. Four texture attributes were correlated with subsets of gross compositional constituents. The availability of information on the manufacturing process increased the interpretability of the models.     

Lipolysis,proteolysis and sensory properties of ewe’s raw milk cheese (Idiazabal) made with lipase addition

In this paper, we describe the effect of the addition of pregastric lipase on the composition and sensory properties of Idiazabal cheese. Free fatty acids (FFA), partial glycerides, free amino acids (FAA), gross composition and sensory characteristics were determined at different ripening times in cheeses manufactured with three different amounts of commercial animal lipase or with lipase-containing artisanal lamb rennet paste. The addition of lipase increased the content of total FFA, particularly of short-chain FFA, and that of total partial glycerides in cheeses. Unexpectedly, lipase utilization significantly affected total FAA concentration, which decreased in cheeses elaborated with high lipase amount. In general, Val, Glu and Leu were the major FAA, and their concentrations depended, mainly, on ripening time. Lipase addition had significant influence on the sensory characteristics of the cheeses, increasing scores for most of the flavour and odour attributes of the cheese. Principal component analysis (PCA) was done including dry matter, FFA, FAA, partial glycerides and odour and flavour attributes of the cheeses. It indicated that aroma and flavour parameters of Idiazabal cheese and the content of short-chain FFA and diglycerides were highly correlated to first principal component (PC1), while texture parameters, compositional variables and FAA were correlated to the second principal component (PC2).     

Chemical and sensory profiles of commercial goat cheeses

This study characterised the chemical and sensory properties of 15 non-spreadable goat cheeses (eight fresh and seven ripened). The majority of the cheeses had a short ripening period. Hence, low free fatty acid (FFA) contents were detected. The main difference among the cheeses was the short-chain FFA content, which was higher in the ripened cheeses, and responsible for their distinctive odours and flavours. In both types of cheeses (fresh and ripened), lactic acid was the most abundant organic acid (OA), followed by propionic acid. Hierarchical cluster analysis identified three distinct groups of samples with marked differences in their texture and flavour attributes. The percentage of moisture was positively correlated to sensory attributes such as surface film, solubility, moistness and sourness, and negatively correlated to the firmness and saltiness. No significant correlation was found among sensory attributes and total fat percentage or any of the OAs.     

Comparison of the volatile composition and sensory characteristics of Spanish PDO cheeses manufactured from ewes’ raw milk and animal rennet

Idiazabal, Manchego, Roncal and Zamorano varieties are the Spanish cheeses manufactured under Protected Denomination of Origin (PDO) from ewes’ raw milk and coagulated with animal rennet. Two batches of each cheese variety were ripened for six months and the cheeses were compared for sensory characteristics and composition of volatile compounds. Seventy-six volatile compounds were identified by GC-MS analysis of headspaces of the cheeses. The volatile profile of the four PDO cheeses differed significantly. Acids were the most abundant volatile compounds in Idiazabal, Roncal, and Zamorano cheeses, whereas alcohols were the main volatile compounds in Manchego cheese due to the large percentage of 2-butanol. Aldehydes, ketones and esters were minor compounds in all the cheese varieties, whereas terpenes and unsaturated hydrocarbons were only found in Manchego cheese. The sensory profiles, of the four PDO cheeses also differed significantly. The highest scores for sharp, brine and rennet odours, and rancid and rennet flavours were assessed in Idiazabal and Zamorano cheeses, whereas milky and buttery odour scores were higher in Manchego, Roncal and Zamorano cheeses than in Idiazabal cheese. Principal component analysis was applied to sensory attributes and volatile composition of the cheeses. Differences in flavour and odour attributes were correlated with differences in the volatile compounds. Two principal components correlating sensory attributes and volatile compounds were defined as “strength factor” and “sweetness factor”. The “strength factor” distinguished among the four cheese varieties, except between Roncal and Manchego cheeses, and the “sweetness factor” distinguished the Zamorano cheese from the Idiazabal, Manchego and Roncal cheeses.     

Changes in lipid fractions and sensory properties of Idiazabal cheese induced by lipase addition

This work studied the addition of an adequate lipase to enhance lipolysis reactions and the development of piquant flavour and sharp odour in Idiazabal cheese, as an alternative to the use of lamb rennet paste. Cheeses were manufactured from bulk raw ewes' milk in 50 l vats with commercial bovine rennet and 80 lipase units of pregastric or 180 lipase units of fungal lipase and ripened for 180 days. A higher lipolytic activity was induced by lipase addition promoting strong changes in odour and flavour attributes. Both fungal and pregastric lipases increased the content of total free fatty acids (FFA), but the fungal lipase released mainly medium- and long-chain FFA. In contrast, the pregastric lipase preferably released short-chain FFA. Diglyceride (DG) content was considerably higher in cheeses made with added pregastric lipase compared with those made with fungal lipase or with no lipase. Monoglycerides (MG) were detected only in cheeses made with either lipase added, reaching comparable concentrations after ripening for 180 days. The cheeses made with pregastric lipase had the highest scores for odour and flavour intensity, and sharp and rennet odours, desirable attributes for the Idiazabal cheese made with lamb rennet paste. None of the texture attributes were significantly influenced by the concentrations of MG and DG in the cheeses made with either lipase. Thus, the pregastric lipase was more appropriate than the fungal lipase to develop a more traditionally-flavoured Idiazabal cheese.     

Free fatty acid composition of regionally-produced Spanish goat cheese and relationship with sensory characteristics

A study was made of free fatty acid composition and sensory characteristics (odour and taste) in regionally-produced Spanish goat cheeses. The most abundant FFAs were oleic, palmitic, stearic, capric and myristic acid which together accounted for roughly 85% of total FFAs. These cheeses generally underwent a lower degree of lipolysis than did other goat cheeses. Panellists judged the cheeses as having considerable odour and flavour intensity. However, both total FFA content and sensory attributes varied considerably among cheeses due, in all likelihood, to differences in ripening time and to production by different manufacturers. Principal component analysis generated three principal components (PC) that accounted for 70% of total variance; the variables that best correlated with them were long-chain and medium-chain free fatty acids (PC1), brine odour, bitterness and goat milk odour (PC2) and short-chain free fatty acids (PC3).     

Influence of ripening temperature on the volatiles profile and flavour of Cheddar cheese made from raw or pasteurised milk

Cheddar cheeses were made from raw (R1, R8) or pasteurised (P1, P8) milk and ripened at 1°C (P1, R1) or 8°C (P8, R8). Volatile compounds were extracted from 6 month-old cheeses and analysed, identified and quantified by gas chromatography-mass-spectrometry. A detailed sensory analysis of the cheeses was performed after 4 and 6 months of ripening. The R8 cheeses had the highest and P1 the lowest concentrations of most of the volatile compounds quantified (fatty acids, ketones, aldehydes, esters, alcohols, lactones and methional). The R8 and P8 cheeses contained higher levels of most of the volatiles than R1 and P1 cheeses. Ripening temperature and type of milk influenced most of the flavour and aroma attributes. Principal component analysis (PCA) of aroma and flavour attributes showed that P1 and R1 had similar aroma and flavour profiles, while R8 had the highest aroma and flavour intensities, highest acid aroma and sour flavour. The age of cheeses influenced the perception of creamy/milky and pungent aromas. PCA of the texture attributes separated cheeses on the basis of ripening temperature. The R8 and P8 cheeses received significantly higher scores for perceived maturity than P1 and R1 cheeses. The P1 and R1 cheeses had similar values for perceived maturity. In a related study, it was found that concentrations of amino acids and fatty acids were similar in R1 and P1 during most of the ripening period, and R1 and P1 cheeses had low numbers of non-starter lactic acid bacteria (NSLAB). The panel found that ripening temperature, type of milk and age of cheeses did not influence the acceptability of cheese. It is concluded that NSLAB contribute to the formation of volatile compounds and affect the aroma and flavour profiles and the perceived maturity of Cheddar cheese.     

Chemical and microbiological status and volatile profiles of mouldy Civil cheese,a Turkish mould‐ripened variety

The objective of this study is to characterise the gross chemical and microbiological status and identify the volatile compounds of mouldy Civil cheeses. A total of forty‐one samples were surveyed, and gross compositional status of the cheeses was (as mean values): 6.5 for pH, 6.2% for fat‐in‐dry matter, 51.8% for moisture and 15.3% for water‐soluble nitrogen (as% of total nitrogen). Chemical composition of the cheese samples varied widely. Mouldy Civil cheese has similar pH values and moisture contents when compared with blue‐type cheeses, but it has distinct feature for fat contents. The microbiological counts of the samples were found to be high and some samples contained coliform bacteria. A total of 95 volatiles, including esters (28), acids (6), ketones (12), aldehydes (3), alcohols (15), terpenes (10), sulphur compounds (3) and miscellaneous (18), were identified in the volatile fractions of the cheeses, and principal volatile groups were esters, alcohols and ketones.     

Sensory characteristics of dudh churpi in relation to its chemical composition

 Dudh churpi, a traditional milk product, had more moisture, fat, water-dispersible protein (WDP), titratable acid, energy, lactic acid, free fatty acids (FFA), 2-thiobarbituric acid (TBA) and tyrosine contents and also reflectance, but less sensory attributes, when prepared in Darjeeling than the products prepared in Sikkim and Bhutan. Sensory attributes were positively correlated with total solids, protein, lactose, sugar, hydroxymethylfurfural (HMF) and p-dimethylaminobenzaldehyde reactivity, and negatively correlated with fat, FFA, TBA, WDP, tyrosine, lactic acid and titratable acidity. Whereas total solids, fat, protein, lactose, glucose-galactose and total sugar accounted for 71% of the flavour score, 64% of the body and texture score, 77% of the colour and appearance score and 77% of the total score, lactic acid, FFA, TBA, tyrosine and HMF jointly reflected variations of 61%, 50%, 81% and 67% in flavour, body and texture, colour and appearance, and total score, respectively. Received: 6 July 1998     

Variations in volatile compounds and flavour in Idiazabal cheese manufactured from ewe's milk in farmhouse and factory

Stage of lactation, use of bulk milk or milk from individual flocks, and cheese‐making in farmhouse or industrial factory are important factors affecting the production and quality of Idiazabal cheese. The volatile composition of cheese samples made from raw ewe's milk in farmhouses or industrial plants at two different times of the year and aged for 90 and 180 days was analysed by dynamic headspace coupled to GC‐MS. Short‐chain fatty acids, primary and secondary alcohols, methyl ketones and ethyl esters were the most abundant compounds in the aroma of Idiazabal cheese samples. Differences in the volatile composition were found between farmhouse and industrial cheeses made at different times of the year and ripened for 90 or 180 days. Likewise, the sensory profiles of the farmhouse and industrial cheeses were significantly different, regardless of the time of the year and ripening time. The results for the principal component analysis (PCA) performed on the sensory attributes of the cheese samples showed two PCs defined as ‘farmhouse flavour factor’ and ‘industrial flavour factor’. Farmhouse cheeses showed high scores for buttery, milky and toasty odours, and buttery and nutty flavours, whereas industrial cheeses showed high scores for sharp, rennet and brine odours, and rennet and rancid flavours. The percentages of methyl ketones such as 3‐hydroxy‐2‐butanone, 2‐butanone, 2‐pentanone and 2‐heptanone, and acids such as n‐propanoic, 2‐methylpropanoic and 3‐methylbutanoic acids were higher in farmhouse cheeses than in industrial cheeses. On the other hand, the percentages of esters such as ethyl butanoate and ethyl hexanoate, and alcohols such as 3‐methyl‐1‐butanol, and acids like n‐hexanoic acid were higher in industrial cheeses than in farmhouse cheeses. Relationships between sensory attributes and volatile compounds were studied on the basis of the differences found in sensory profile and volatile composition between farmhouse and industrial cheeses. Copyright © 2005 Society of Chemical Industry     

Determination of volatile compounds and quality parameters of traditional Istrian dry-cured ham

The aim of this work was to determine the characteristics of Istrian dry-cured ham by instrumental methods and sensory analysis. The aroma-active compounds of Istrian dry-cured ham from 2010 and 2012 were investigated by using headspace-solid phase microextraction (SPME) and gas chromatography–mass spectrometry (GC–MS). Samples of biceps femoris were also evaluated by measuring physical and chemical characteristics. 92 volatile aroma compounds of Istrian dry-cured ham were found. Volatile compounds belonged to several chemical groups: aldehydes (51.4; 51.3%), terpenes (16.5; 16.4%), alcohols (15.5; 13.2%), ketones (8.6; 7.4%), alkanes (3.8; 5.7%), esters (1.3; 1.6%), aromatic hydrocarbons (0.8; 3.9%) and acids (0.6; 0.9%). Principal component analysis (PCA) showed that fat content, tenderness and melting texture were positively correlated. Terpenes were strongly correlated with flavour of added spices. Sweet taste and the presence of esters were positively correlated as well as negative odour, raw meat flavour and water content.