Effect of packaging materials and storage on major volatile compounds in three Australian native herbs

Trends and challenges in the development of bio-based barrier coating materials for paper/cardboard food packaging; a review

Currently, petroleum-based synthetic plastics are used as a key barrier material in the paper-based packaging of several food and nonfood goods. This widespread usage of plastic as a barrier lining is not only harmful to human and marine health, but it is also polluting the ecosystem. Researchers and food manufacturers are focused on biobased alternatives because of its numerous advantages, including biodegradability, biocompatibility, non-toxicity, and structural flexibility. When used alone or in composites/multilayers, these biobased alternatives provide strong barrier qualities against grease, oxygen, microbes, air, and water. According to the most recent literature reports, biobased polymers for barrier coatings are having difficulty breaking into the business. Technological breakthroughs in the field of bioplastic production and application are rapidly evolving, proffering new options for academics and industry to collaborate and develop sustainable packaging solutions. Existing techniques, such as multilayer coating of nanocomposites, can be improved further by designing them in a more systematic manner to attain the best barrier qualities. Modified nanocellulose, lignin nanoparticles, and bio-polyester are among the most promising future candidates for nanocomposite-based packaging films with high barrier qualities. In this review, the state-of-art and research advancements made in biobased polymeric alternatives such as paper and board barrier coating are summarized. Finally, the existing limitations and potential future development prospects for these biobased polymers as barrier materials are reviewed.

Comparison of the ability of UV-Vis and UPLC-Q-TOF-MS combined with chemometrics to discriminate recycled and virgin polyethylene

A growing attention is attracted to the use of recycled plastics as food contact materials, and its chemical safety research and discrimination approach are indispensable. In current study, ultraviolet-visible spectrometry (UV-Vis) and ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) were used to provide spectral and mass fingerprinting for polyethylene (PE). Coupling with chemometrics, two methods were developed to discriminate recycled and virgin PE. UV-Vis combined with chemometrics could be a more accessible, simpler and faster approach. 237-331 nm in UV spectrum was regarded as marker region selected by orthogonal partial least-squares discrimination analysis (OPLS-DA) and the accuracy of both calibration and validation set could reach 100% in linear discrimination analysis (LDA) based on this region. Besides, 2314 ions were detected by UPLC-Q-TOF-MS and processed by MS-DIAL. 48 candidate chemicals were identified, including ketone, esters, carboxylic acid, alcohols and phenols, amine, nitriles, aldehydes and others. Possible origins of these compounds could be classified as plastic, food, drug, cosmetics and pesticide related. Many of these compounds are highly toxic, especially pesticide related, indicating that recycling in closed loop or sorting by the recycled plastic articles is very necessary if the recycled PE is going to be used as food contact material.

The Framework for Responsible Research With Australian Native Plant Foods: A Food Chemist's Perspective

Australia is a rich source of biodiverse native plants that are mostly unstudied by western food science despite many of them being ethnofoods of Australian Indigenous people. Finding and understanding the relevant policy and legal requirements to scientifically assess these plants in a responsible way is a major challenge for food scientists. This work aims to give an overview of what the legal and policy framework is in relation to food chemistry on Australian native plant foods, to clarify the relationships between the guidelines, laws, policies and ethics and to discuss some of the challenges they present in food chemistry. This work provides the framework of Indigenous rights, international treaties, federal and state laws and ethical guidelines including key legislation and guidelines. It discusses the specific areas that are applicable to food chemistry: the collection of plant foods, the analysis of the samples and working with Indigenous communities. This brief perspective presents a framework that can be utilized by food chemists when developing responsible research involving plant foods native to northern Australia and can help them understand some of the complexity of working in this research area.

Anti-Yeast Synergistic Effects and Mode of Action of Australian Native Plant Essential Oils

Yeasts are the most common group of microorganisms responsible for spoilage of soft drinks and fruit juices due to their ability to withstand juice acidity and pasteurization temperatures and resist the action of weak-acid preservatives. Food industries are interested in the application of natural antimicrobial compounds as an alternative solution to the spoilage problem. This study attempts to investigate the effectiveness of three Australian native plant essential oils (EOs) Tasmanian pepper leaf (TPL), lemon myrtle (LM) and anise myrtle (AM) against weak-acid resistant yeasts, to identify their major bioactive compounds and to elucidate their anti-yeast mode of action. The minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC) and minimum bactericidal concentration (MBC) were assessed for EOs against weak-acid resistant yeasts (Candida albicans, Candida krusei, Dekkera anomala, Dekkera bruxellensis, Rhodotorula mucilaginosa, Saccharomyces cerevisiae, Schizosaccharomyces pombe, Zygosaccharomyces bailii and Zygosaccharomyces rouxii) and bacteria (Staphylococcus aureus and Escherichia coli). The EOs showed anti-yeast and antibacterial activity at concentrations ranging from 0.03–0.07 mg/mL and 0.22–0.42 mg/mL for TPL and 0.07–0.31 mg/mL and 0.83–1.67 mg/mL for LM, respectively. The EOs main bioactive compounds were identified as polygodial in TPL, citral (neral and geranial) in LM and anethole in AM. No changes in the MICs of the EOs were observed in the sorbitol osmotic protection assay but were found to be increased in the ergosterol binding assay after the addition of exogenous ergosterol. Damaging of the yeast cell membrane, channel formation, cell organelles and ion leakage could be identified as the mode of action of TPL and LM EOs. The studied Australian native plant EOs showed potential as natural antimicrobials that could be used in the beverage and food industry against the spoilage causing yeasts.

Essential oil constituents and variations in antioxidant compounds of dried summer savory (Satureja hortensis cv. Saturn) affected by storage conditions and ammonium sulfate

Considering the importance of spice plants and their shelf life, as affected by various factors, the current study considered Summer savory plants (Satureja hortensis cv. Saturn) for evaluation under the application of different concentrations of ammonium sulfate (0, 40, 60, 80, and 100 kg/ha) as primary treatments. Based on the plant response, the control group and 100 kg/ha ammonium sulfate were selected as suitable treatments for storage experiments (i.e., storage at ambient, refrigerator, and freezer temperatures for 8 months). Based on the results, the highest percentage and yield of S. hortensis essential oil and biomass occurred in response to 100 kg ammonium sulfate, whereas the lowest amounts were observed in the control group (i.e., in the absence of ammonium sulfate). During the storage period, the essential oil content decreased, but the carvacrol content of the essential oil increased. During the different durations and conditions of storage, the stability of secondary metabolites varied. Essential oil, rosmarinic acid, and carvacrol contents maintained greater stability in plants treated with ammonium sulfate (100 kg/ha), compared with the control group during the storage period. It can be concluded that the preharvest application of ammonium sulfate on S. hortensis improved plant growth and quality indices at preharvest time, while also maintaining the stability of its active ingredients at the postharvest stage and storage time. It also led results to recommend storing Summer savory in the freezer to better preserve its secondary metabolites.

Effects of storage on the oxidative stability of acorn oils extracted from three different Quercus species

BACKGROUND

Acorn fruit and its components and by-products are receiving renewed interest due to their nutritional and phytochemical features. In particular, the oil extracted from acorns is recognized for having high nutritional quality and for being rich in bioactive compounds. Despite the growing interest, few papers are available that consider the evolution of acorn-oil characteristics during storage. Our aim was to investigate the storage-related changes in acorn oils extracted from three Quercus species grown in Algeria (Q. ilex, Q. suber, and Q. coccifera) 180 days after production, with a focus on polar and volatile compounds, not yet investigated. Basic quality parameters, phenolic content, antioxidant activity and induction time were also monitored.

RESULTS

The oxidation markers (peroxide value and UV absorptions) increased during storage, whereas antioxidants decreased. A distinctive volatile profile was observed at the time of production, which underwent changes during storage. Polar compounds increased, whereas induction time decreased. The oil extracted from Quercus suber L. was the most affected by storage time.

CONCLUSION

Floral and fruity volatile compounds detected in the oils' headspace could explain the pleasant flavor of acorn oils reported by other authors. As with other vegetable oils, storage depletes both volatiles and antioxidants and produces oxidation compounds, such as oxidized triacylglycerols. However, the acorn oils that were studied were quite stable under storage in the dark at room temperature for 6 months. © 2020 Society of Chemical Industry.

Changes in volatile compounds, sugars and organic acids of different spices of peppers (Capsicum annuum L.) during storage

Changes in sugars, organic acids and volatile compounds (VC) of red pepper flakes (RPF), traditional (TRI), and industrial (INI) isot peppers were evaluated during one year storage at the room condition. The changes in the flavor components were significantly affected by the production methods and storage time. Glucose content decreased gradually along storage and reduced by about 21.23, 47.22 and 56.65% for TRI, INI and RPF, respectively. However, fructose decreased significantly only in RPF (11.29%). Citric and succinic acids exhibited slight changes, but malic acid showed an increasing trend, especially in RPF (4-fold). Most of the VC in all samples decreased or disappeared after storage. The major quantitative losses in these compounds were found in TRI during the first 3 months as 81.76%. The storage was found to be caused deterioration flavor properties in red pepper spices and revealed the importance of appropriate storage conditions.

Scalping of aroma compounds from food simulants into polyethylene terephthalate laminated steel

BACKGROUND

Aroma scalping is a very common problem and can affect the sensory quality of packaged food. To study the aroma scalping characteristics of polyethylene terephthalate laminated steel (PET-LS), the sorption kinetics of six common aroma compounds (2-pentanone, 2-heptanone, hexanal, citral, butyl acetate, isopentyl acetate) in foods were assessed for drawn-redrawn cans made with PET-LS.

RESULTS

Storage temperature and initial concentration were proved as important factors to affect compound sorption and diffusion for flavors. The correlation between logarithm of equilibrium absorption ln M_∞ and reciprocal of absolute temperature 1/T showed good linear relationship (R²  = 0.9380-0.9998) at 4 °C, 20 °C and 50 °C, and the M_∞ obtained by the experiment was very close to the predicted value at 37 °C. At low initial concentration (below 500 µL L^-1 ), the absorption capacity and initial concentration showed a slow linear growth trend, whereas there was a rapid change at high initial concentration. The values of diffusion coefficient D were on the order of 10^-11 -10^-12  m²  day^-1 , which were lower than reported for other polymer materials (linear low-density polyethylene, polybutylene succinate, polylactic acid).

CONCLUSION

The equilibrium absorption amount of each flavor component was dependent on the temperature under the same concentration (500 µL L^-1 ). The Fickian diffusion model was used for fitting the experimental kinetics values satisfactorily (R²  = 0.9158-0.9885). © 2019 Society of Chemical Industry.

Packaging methods and storage duration affect essential oil content and composition of lemon verbena (Lippia citriodora Kunth.)

Changes in essential oils (EOs) content and composition of lemon verbena leave at different packaging methods (packaged with air, nitrogen, or under vacuum) and during storage period (0, 2, 4, 6 and 8 months) were determined. All the samples were hydrodistilled every 2 months during storage for EO content evaluation. EO composition was determined by gas chromatography and gas chromatography-mass spectrometry. The results showed that by extending the storage period in all packaging methods, EO content was significantly decreased. Parallel to the increase in the storage duration in all packaging methods, citral content was decreased, whereas the amounts of limonene and 1,8-cineole were increased. Packaging of lemon verbena leaves with nitrogen preserved the highest EO content during 8 months of storage and achieved the desired amounts of citral, limonene, and 1,8-cineole. This investigation also showed camphene may be a useful marker for the indication of storage duration of lemon verbena.

Effects of packaging materials on the aroma stability of Thai 'tom yam' seasoning powder as determined by descriptive sensory analysis and gas chromatography-mass spectrometry

BACKGROUND

Changes in the aroma characteristics of Thai 'tom yam' seasoning powder, containing lemongrass, galangal and kaffir lime leaf, as affected by different packaging materials were assessed using quantitative descriptive analysis (QDA) and gas chromatography-mass spectrometry (GC-MS). The descriptive aroma attributes for lemongrass, galangal and kaffir lime leaf powders were developed by the QDA panel. The mixed herb and spice seasoning powder was kept in glass jars closed with different packaging materials (Nylon 6, polyethylene terephthalate (PET) and polylactic acid (PLA)) stored at 38 °C (accelerated storage condition), and evaluated by the trained QDA panel during storage for 49 days.

RESULTS

The descriptive words for Thai 'tom yam' seasoning powder developed by the trained panelists were lemongrass, vinegary and leafy for lemongrass, galangal and kaffir lime leaf dried powder, respectively. The aroma intensities significantly (P ≤ 0.05) decreased with increased storage time. However, the intensity scores for aroma attributes were not significantly (P > 0.05) different among the packaging materials studied. The major components in Thai 'tom yam' seasoning powder, quantified by GC-MS, were estragole, bicyclo[3.1.1]heptane, β-bisabolene, benzoic acid and 2-ethylhexyl salicylate. The concentrations of major aroma compounds significantly (P ≤ 0.05) decreased with storage time.

CONCLUSION

Aroma stability of Thai 'tom yam' powder can be determined by descriptive sensory evaluation and GC-MS analysis. Nylon, PET and PLA exhibited similar aroma barrier properties against key aroma compounds in Thai 'tom yam'. This information can be used for prediction of aroma loss through packaging materials during storage of Thai 'tom yam'. © 2016 Society of Chemical Industry.