An accurate quantitative method for the analysis of terpenes in milk fat by headspace solid-phase microextraction coupled to gas chromatography–mass spectrometry

A quantitative review of on-farm feeding practices to enhance the quality of grassland-based ruminant dairy and meat products

In the last decades, a large body of evidence has highlighted the major role of feeding management practices in improving specific nutritional, technological and sensory quality traits of ruminant products. However, results have been mostly obtained under controlled conditions, and have been rarely validated on-farm. Therefore, a quantitative review was conducted to quantify the effects of on-farm feeding management practices on carotenoids, fat-soluble vitamins, colour, fatty acids (FAs), terpenes and sensory properties in the main animal product categories (PCs): dairy products from cattle (DC), sheep (DS) and goat (DG), and meat from cattle (MC) and sheep (MS). Four feeding scenarios were selected according to the consistency of on-farm studies in the literature: (a) feeding "Fresh herbage" instead of conserved forages; (b) ban any form of silage ("Silage-free"); (c) ban maize silage ("Maize silage-free"); (d) feeding forages from permanent grasslands rich in species or plant secondary metabolites (PSMs) ("PSM-rich permanent grassland"). Feeding fresh herbage increased the concentration of carotenoids, fat-soluble vitamin, n-3 FA, rumenic acid, and branched chain FA (BCFA), and reduced the concentration of saturated FA, for all PC, with overall stronger effect for dairy products than for meat. The texture of meat and dairy products was marginally affected, whereas feeding fresh herbage decreased lactic and increased vegetal notes in DC. The "Silage-free" feeding scenario resulted in increased vaccenic acid, rumenic acid, BCFA, and C18:3n-3 in DC. The "Maize silage-free" feeding scenario lowered n-6 FA whereas increased n-3, rumenic acid and BCFA concentrations in DC. Feeding ruminants with forages from "PSM-rich permanent grasslands" increased monounsaturated FA, n-3 FA and rumenic acid and decreased n-6 FA in dairy products, and only marginally affected meat FA composition. The DC from "PSM-rich permanent grasslands" showed higher intense, spicy and animal notes. Overall, the differences between feeding management practices observed on farm were smaller than those observed under controlled trials. Several confounding factors, not controlled when operating under on-farm conditions, could be at the origin of these divergences (i.e. mixed diets, forage characteristics, animal-related factors). This review confirmed that farming practices may differently affect several quality traits of ruminant products. It also highlighted the uneven knowledge on the effect of feeding management depending on the PC: larger for milk than for meat and decreasing when moving from cattle to sheep and from sheep to goat.

Development of New HS–SPME–GC–MS Technique to the Measurement of Volatile Terpenoid Profile of Milk

This study presented the development of such a HS–SPME–GC–MS technique, with the use of which, directly from the raw milk sample matrix, both qualitatively and quantitatively; the volatile terpenoids (α-pinene, sabinene, β-pinene, p-cymene, limonene, linalool, α-thujene, camphor, menthol, methyl chavicol, caryophyllene E, α-humulene) can be determined, derived from herbs eaten by the dairy animals by different feeding methods. Repeatability was less than 10% in the case of milk fat samples. The estimated limits of quantitation were between 2 and 16 ng/g. The lowest values were 2 ng/g for p-cymene and methyl chavicol; the highest value was 16 ng/g for caryophyllene. In the case of goat milk, the repeatability was better than 8% except for α-thujene. The estimated limits of quantitation were between 1 and 8 ng/g. The lowest values were 1 ng/g for β-pinene, p-cymene and limonene, and the highest value was 8 ng/g for linalool. In milk fat, the highest concentration was identified in caryophyllene E (470 ng/g) and α-humulene (430 ng/g), while the lowest concentration was in p-cymene (2 ng/g) and camphor (2 ng/g). In goat milk, limonene was present in all samples, but its amount varied depending on the type of consumed herb. Methyl chavicol and caryophyllene E were detected in goat’s milk only in one case. The former was detected in sage milk at 2.09 ng/g and the latter in tarragon milk at 2.28 ng/g. We have also successfully demonstrated that the feed consumed by dairy animals also affects the quality of dairy products.

Evaluation of Terpenes' Degradation Rates by Rumen Fluid of Adapted and Non-adapted Animals

The aim of the present study was to evaluate terpenes degradation rate in the rumen fluid from adapted and non-adapted animals. Four castrated healthy animals, two rams and two bucks, were used. Animals were daily orally dosed for 2 weeks with 1 g of each of the following terpenes, α-pinene, limonene and β-caryophyllene. At the end of each week, rumen fluid (RF) samples were assayed in vitro for their potential to degrade terpenes over time. For each animal, a 10 mL reaction medium (RM) at a ratio 1:9 (v/v) was prepared and a terpenes solution at a concentration of 100 μg/ml each, was added in each RM tube. Tubes were incubated at 39 °C under anaerobic conditions and their contents sampled at 0, 2, 4, 8, 21 and 24 h. RF could degrade terpenes as it was shown by the significantly (P < 0.05) higher overall degradation rates. Individual terpene degradation rates, were significantly (P < 0.05) higher in week 5 for limonene and marginally (P = 0.083) higher also in week 5 for α-pinene. In conclusion, the findings of the present preliminary study suggest that terpenes can be degraded in the rumen fluid.

Accelerated Solvent Extraction of Terpenes in Cannabis Coupled With Various Injection Techniques for GC-MS Analysis

The cannabis market is expanding exponentially in the United States. As state-wide legalization increases, so do demands for analytical testing methodologies. One of the main tests conducted on cannabis products is the analysis for terpenes. This research focused on implementation of accelerated solvent extraction (ASE), utilizing surrogate matrix matching, and evaluation of traditional vs. more modern sample introduction techniques for analyzing terpenes via gas chromatography–mass spectrometry (GC-MS). Introduction techniques included Headspace-Syringe (HS-Syringe), HS-Solid Phase Microextraction Arrow (HS-SPME Arrow), Direct Immersion-SPME Arrow (DI-SPME Arrow), and Liquid Injection-Syringe (LI-Syringe). The LI-Syringe approach was deemed the most straightforward and robust method with terpene working ranges of 0.04–5.12 μg/mL; r² values of 0.988–0.996 (0.993 average); limit of quantitation values of 0.017–0.129 μg/mL (0.047 average); analytical precisions of 2.58–9.64% RSD (1.56 average); overall ASE-LI-Syringe-GC-MS method precisions of 1.73–14.6% RSD (4.97 average); and % recoveries of 84.6–98.9% (90.2 average) for the 23 terpenes of interest. Sample workflows and results are discussed, with an evaluation of the advantages/limitations of each approach and opportunities for future work.

Effect on the Antioxidant, Lipoperoxyl Radical Scavenger Capacity, Nutritional, Sensory and Microbiological Traits of an Ovine Stretched Cheese Produced with Grape Pomace Powder Addition

An innovative ovine cheese enriched with red grape pomace powder (GPP) was produced to improve the functional properties of Vastedda cheese typology. Vastedda cheese making was performed adding GPP and four selected Lactococcus lactis strains (Mise36, Mise94, Mise169 and Mise190). For each strain, 40 L of pasteurized ewe's milk was divided into two aliquots representing control and experimental trials. Control cheese (CC) production did not contain GPP, while the experimental cheese (EC) production was enriched with 1% (w/w) GPP. GPP did not slow down starter development and acid generation. Plate counts and randomly amplified polymorphic DNA (RAPD)-PCR analysis confirmed the dominance of the starters in all trials. The evolution of the physicochemical parameters showed that EC productions were characterized by lower fat content, higher protein content, and higher values of secondary lipid oxidation. Sensory evaluation indicated that the cheeses produced with the strain Mise94 were those more appreciated by the judges. Thus, the last cheeses were investigated for some functional aspects: GPP enrichment significantly increased antioxidant activity and lipoperoxyl radical scavenger capacity, confirming that grape polyphenol inclusion in cheese represents an optimal strategy for the valorization of ovine cheeses as well as winemaking industry by-products.

Terpenoid traceability of commercial sheep cheeses produced in mountain and valley farms: From pasture to mature cheeses

Mountain cheeses are characterized by their strong link to the territory and are testimonial of the cultural heritage. However, there is a lack of traceability and authenticity indicators for most mountain cheeses produced in Europe even though their terroir value is demanded by cheese-makers, consumers and regulatory bodies. The present study investigated the potential and reliability of terpenoids as traceable compounds in Idiazabal PDO cheeses made with raw milk from commercial sheep flocks grazed on lowlands or mountain grasslands. Terpenoids were analysed in individual pasture plants and ripened cheeses. Ingested diets were estimated by microscopic examination of plant residues in sheep faeces, and terpenoid composition of pastures and sheep diets were calculated from isolated plant species analysis. About 100 individual terpenoids were detected in botanical species collected from pastures and 40 compounds in mature cheeses. Important differences were found in the abundance of terpenoids identified in lowland and highland pastures mainly depending on the botanical family and the contribution of each botanical species to both type of grasslands. Estimated sheep diet composition of lowland and highland flocks was different and, in consequence, ingested terpenoids calculated from the estimated diet composition and individual plant terpene analysis were different. The multivariate approach provided robustness in the terpenoid traceability from pasture to cheese selecting individual terpenoids, particularly sesquiterpenoids such as γ-cadinene and aromadendrene, which strongly contributed to discriminate between mountain and valley cheeses. These results can help regulatory bodies to implement effective traceability and authentication procedures to identify mountain cheeses and to protect added-value dairy products.

Effect of season on fatty acid and terpene profiles of milk from Greek sheep raised under a semi-extensive production system

The objective of the study was to investigate the effect of season on the fatty acid and terpene composition in ewe milk. A total of 760 samples of bulk sheep milk were collected during winter (147 samples), spring (314 samples) and summer (299 samples) of 2011, from 90 commercial farms of dairy sheep from the prefecture of Grevena, Greece. Regarding fatty acid composition, summer samples had higher concentrations of α-linolenic acid, cis-9, trans 11- CLA, trans-11, C18 : 1 and PUFAs but lower content of saturated fatty acids particularly C12 : 0, C14 : 0 and C16 : 0. The winter milk had the lowest content of terpenes, in particular sesquiterpenes, compared to spring and summer milk. The terpene profile of milk samples, in all three seasons, revealed the presence of monoterpenes: a-pinene, b-pinene and D-limonene, especially with a higher frequency of appearance in summer. The most common and abundant sesquiterpenes found in milk samples were β-caryophyllene and α-caryophyllene with a higher frequency of appearance in summer. In conclusion, the available pastures in semi-extensive farming systems can contribute to the production of high quality milk.

Application of response surface methodology to optimize solid-phase microextraction procedure for chromatographic determination of aroma-active monoterpenes in berries

Most of scientific papers concern the qualitative or semi-quantitative analysis of aroma-active terpenes in liquid food matrices. Therefore, the procedure based on solid-phase microextraction and two-dimensional gas chromatography-time-of-flight mass spectrometry for determination of monoterpenes in fresh berries was developed. The optimal extraction conditions using divinylbenzene-carboxen-polydimethylsiloxane fiber were: temperature of 50°C, extraction time of 26min, equilibrium time of 29min. The developed procedure provides a high recovery (70.8-99.2%), good repeatability (CV<10.4%), high linearity (r>0.9915) and offers practical advantages over currently used methods: reliability of compounds identification, simplicity of extraction and at least one order of magnitude lower detection limits (0.10-0.011μg/L). The method was successfully applied to determine monoterpenes in 27 berry samples of different varieties and 4 berry products. Tukey's test revealed that monoterpenes content is a reliable indicator of fruit maturity and origin. It suggests that the method may be of interest to researchers and food industry.

Variation of terpenes in milk and cultured cream from Norwegian alpine rangeland-fed and in-door fed cows

The terpene content of milk and cream made from milk obtained from cows fed indoors, and by early or late grazing, in alpine rangeland farms in Norway, were analysed for three consecutive years. The main terpenes identified and semi-quantified were the monoterpenes β-pinene, α-pinene, α-thujene, camphene, sabinene, δ-3-carene, d-limonene, γ-terpinene, camphor, β-citronellene, and the sesquiterpene β-caryophyllene. The average total terpene content increased five times during the alpine rangeland feeding period. The terpenes α-thujene, sabinene, γ-terpinene and β-citronellene were only detected in milk and cultured cream from the alpine rangeland feeding period and not in samples from the indoors feeding period. These four terpenes could be used, as indicators, to show that milk and cultured cream originate from the alpine rangeland feeding period. The terpenes did not influence the sensorial quality of the milk or the cultured cream.

Transfer of orally administered terpenes in goat milk and cheese

The objective of the present study was to investigate the relationships between terpenes’ intake and their presence in animal tissues (blood and milk) as well as in the final product (cheese). Eight dairy goats were divided in two balanced groups, representing control (C) and treatment (T) group. In T group oral administration of a mixture of terpenes (α-pinene, limonene and β-caryophyllene) was applied over a period of 18 d. Cheese was produced, from C and T groups separately, on three time points, twice during the period of terpenes’ oral administration and once after the end of experiment. Terpenes were identified in blood by extraction using petroleum ether and in milk and cheese by the use of solid phase micro-extraction (SPME) method, followed by GC-MS analysis. Chemical properties of the milk and the produced cheeses were analyzed and found not differing between the two groups. Limonene and α-pinene were found in all blood and milk samples of the T group after a lag-phase of 3 d, while β-caryophyllene was determined only in few milk samples. Moreover, none of the terpenes were traced in blood and milk of C animals. In cheese, terpenes’ concentrations presented a more complicated pattern implying that terpenes may not be reliable feed tracers. We concluded that monoterpenes can be regarded as potential feed tracers for authentification of goat milk, but further research is required on factors affecting their transfer.

Volatile compounds of Van Herby cheeses produced with raw and pasteurized milks from different species

Levels of volatile compounds in Van herby cheeses manufactured from raw and pasteurized; 100 % ewes', 50 % ewes'+50 % cows' and mixture of 50 % ewes'+25 % cows'+25 % goats' milks were investigated over 180 days of ripening at 4 °C. The volatile compounds levels of herby cheese samples increased throughout the 180 days storage period. Samples produced from pasteurized milk showed lower volatile contents than their counterparts produced from raw milk. The volatile compounds profile of herby cheese samples detected by headspace solid-phase microextraction (HS-SPME) consisted of 8 esters, 5 ketones, 5 aldehydes, 9 acids, 6 alcohols and 14 hydrocarbons and terpenes. Acetic acid was the most abundant volatile compound in HS-SPME of ripened cheeses, followed by hexanoic, octanoic and butanoic acids.

Effects of seasonal changes in feeding management under part-time grazing on terpene concentrations of ewes' milk

Terpene composition of ewes’ raw milk from nine commercial flocks was analysed from February to July. Ewes’ diet consisted of concentrate and conserved forage in winter (indoor feeding) and part-time grazing from spring (transition and outdoor feeding). Regardless of the feeding, limonene and β-phellandrene were the most abundant monoterpenes and β-caryophyllene showed the highest concentrations among sesquiterpenes. Terpene content increased in the milks of commercial flocks when animals were reared under grazing management. Monoterpenes were detected in the milks of all the commercial flocks throughout the season, whereas sesquiterpenes were only detected in the milks from flocks grazing on non-cultivated community-owned grasslands in which a higher biodiversity of plant species grew. These preliminary results indicated that β-caryophyllene could be a potential pasture-diet marker in the case of milks from animals grazing a higher biodiversity of plant species but in-depth studies including information on terpene composition of plants ingested by the animals are necessary to evaluate the suitability of β-caryophyllene or another terpenoid compound as pasture biomarker.