Application of headspace solid-phase micro-extraction gas chromatography for the assessment of the volatiles profiles of ultra-high temperature hydrolysed-lactose milk during production and storage

Abstract

UHT hydrolysed-lactose milk (HLM) is prone to chemical changes, giving rise to off-flavours in the product. To investigate this better, headspace solid-phase micro-extraction gas chromatography (HS-SPME/GCeMS) was applied to monitor the volatiles profile of HLM during production and shelf-life. Optimum extraction conditions for volatiles were explored, focussing on compounds affecting milk aroma. This study is the first investigating industrial scale manufacturing under controlled conditions, allowing direct associations between specific reactions and changes in milk volatiles. The effect of UHT treatment on milk flavour was shown, while the lactase, potentially containing undesirable proteases and odours, did not alter the milk "volatilome" after addition. Commercial samples exhibited different trends in the volatiles along the shelf-life due to differences in production systems, lactase purity and packaging. Merging all results, HS-SPME/GCeMS successfully mapped the phenomena causing modifications in the volatiles profile of UHT HLM at each step of the product life-cycle.

Chemical and sensory changes during shelf-life of UHT hydrolyzed-lactose milk produced by “in batch” system employing different commercial lactase preparations

“…Analysis of the volatiles organic compounds (VOCs) was performed by SPME GC-MS according to Bottiroli, Aprea, Betta, Fogliano, & Gasperi (2020). Five mL of sample were placed into 20 mL glass vials for gas-chromatography (Supelco, Bellefonte, PA,) and 4-methyl-2pentanone was chosen as internal standard.…”

Understanding the effect of storage temperature on the quality of semi-skimmed UHT hydrolyzed-lactose milk: an insight on release of free amino acids, formation of volatiles organic compounds and browning

“…An increase in the concentration of methyl ketones, aldehydes and organic acids during storage appeared as major responsible for the development of this sensory defect in UHLM (Bottiroli, Troise, et al, 2020;Jensen et al, 2015). Our group estimated these VOCs in UHLM both by HS SPME GC-MS and PTR-TOF-MS, outlining that off-flavors are created mostly alongside Strecker degradation (Bottiroli, Aprea, Betta, Fogliano, & Gasperi, 2020;Bottiroli, Pedrotti, et al, 2020).…”

Relationship between Sensory Attributes, (Dis) Liking and Volatile Organic Composition of Gorgonzola PDO Cheese

“…Then, a 7 g sample was introduced in a 20 mL glass vial, spiked with 50 µL of a solution of 4-methyl-2-pentanone (Aldrich, Milan, Italy) used as an internal standard (IS). The volatile compounds were measured according to Bottiroli et al [31] with a slight modification of the temperature program. In brief, after 30 min of equilibration at 40 • C, the SPME fiber (2 cm, DVB-Carboxen-PDMS, SUPELCO, Bellefonte, PA, USA) was inserted in the headspace of the vial for 30 min and then desorbed at 250 • C in the injector port of a GC interfaced with a mass detector operating in an electron ionization mode (EI: 70 eV) (GC Clarus 500, PerkinElmer, Norwalk, CT, USA).…”