Superficial scald development in 'Granny Smith' and 'Nicoter' apples: The role of key volatile compounds when fruit are stored under dynamic controlled atmosphere.

A positive correlation of α-farnesene and its oxidation metabolites with superficial scald is commonly reported in apples stored in air or controlled atmosphere (CA) systems, where O2 levels are above the lower oxygen limit (LOL) tolerated by the fruit. Nevertheless, the LOL can be monitored by the dynamic controlled atmosphere (DCA) techniques and to provide different physiological responses. Therefore, this study aimed to evaluate key volatile metabolites from 'Granny Smith' and 'Nicoter' ('Kanzi®') apples stored under dynamic controlled atmosphere (DCA) monitored by respiratory quotient (RQ), i. e. at extremely low oxygen partial pressures (ELO) and correlate their emissions with the incidence of superficial scald (SS). The volatile compounds (VCs) were isolated by solid phase microextraction (HS-SPME) and analyzed by gas chromatography. For the first time, higher concentrations of α-farnesene and its oxidation metabolites (6-methyl-5-hepten-2-one, and 6-methyl-5-hepten-2-ol) were negatively correlated with SS in DCA-RQ. This is likely due to the higher levels of ethanol in fruit stored under this condition having an inhibitory effect on SS incidence even when α-farnesene, 6-methyl-5-hepten-2-one, and 6-methyl-5-hepten-2-ol accumulate. Additionally, SS is more correlated to internal ethylene concentration (IEC) than α-farnesene accumulation and their metabolites, even when fruit were stored under ELO, where ethylene action is reduced.

The isolated or combined effects of dynamic controlled atmosphere (DCA) and 1-MCP on the chemical composition of cuticular wax and metabolism of 'Maxi Gala' apples after long-term storage.

Apples have a continuous hydrophobic layer that covers the surface of the fruit, which is called the cuticle. The effects of 1-methylcyclopropene (1-MCP) on the cuticular wax layer of apples were reported after cold storage, although the interaction between 1-MCP and dynamic controlled atmosphere (DCA) is not yet known. Therefore, this study aimed to analyze the effects of 1-MCP on the wax composition and metabolism of 'Maxi Gala' apples after storage in a controlled atmosphere (CA) and dynamic controlled atmosphere based on chlorophyll fluorescence (DCA-CF) and respiratory quotient (DCA-RQ; RQ = 1.3 and 1.5). The 1-MCP treatment effectively decreased ethylene production for CA and DCA-CF treatments, while in DCA-RQ treatments produced no effect. The average extracted cuticular wax content of 'Maxi Gala' apples was 16.65 g m-2 and no differences in storage conditions or 1-MCP application were observed. Alkanes, alcohols, fatty acids, aldehydes, and terpenoids were identified in the chemical composition of the cuticular waxes, being alkanes and fatty acids the predominant ones. Moreover, 1-MCP decreased fatty acid and 10-nonacosanol concentrations in the fruit. Fruit with the 1-MCP application and stored in DCA had lower α-farnesene concentrations. The wax compositions of the DCA-stored apples with and without 1-MCP were similar. However, 1-MCP treatment resulted in a greater mass loss in fruit stored in DCA.

Effect of ultrasound on proteolysis and the formation of volatile compounds in dry fermented sausages.

Ultrasound (US) is an emerging technology capable of affecting enzymes and microorganisms, leading to the release of amino acids and the formation of volatile compounds. The effect of different exposure times (0, 3, 6, and 9 min) of US (25 kHz, 128 W) on the proteolysis and volatile compounds of dry fermented sausages during processing (day 0 and 28) and storage (day 1 and 120) was investigated. Lower alanine, glycine, valine, leucine, proline, methionine, and tyrosine levels were observed at the beginning of manufacture for the sample subjected to 9 min of US (p < 0.05) when compared to the control. During the storage period, the samples subjected to US exposure for 3 and 6 min exhibited higher free amino acid levels. A greater formation of hexanal, pentanal, and hexanol was observed in the US-treated samples when compared to the control (p < 0.05), as well as other derivatives from the oxidation reactions during the storage. The use of US (25 kHz and 128 W) in the manufacture of dry fermented sausages can affect the proteolysis and the formation of compounds derived from lipid oxidation during the storage.

Key volatile compounds of 'Fuji Kiku' apples as affected by the storage conditions and shelf life: Correlation between volatile emission by intact fruit and juice extracted from the fruit.

For the 'Fuji Kiku' apple, this study aimed: (i) to evaluate the volatile compounds (VCs) from headspace storage chambers with static controlled atmosphere (CA) and with dynamic controlled atmosphere based on chlorophyll fluorescence (DCA-CF) and based on respiratory quotient (DCA-RQ1.5) at ninth month of storage, during 1 and 7 days of shelf life of intact fruit, and in apple juice headspace and (ii) to determine the correlation of the VCs in the headspace from storage chambers and fruit during shelf life with the headspace VCs from apple juice as markers of quality. The VCs were isolated by solid phase microextraction (HS-SPME) and analyzed by gas chromatography. In the storage chambers, ethyl linear chain esters were detected mainly in DCA-RQ1.5, while acetaldehyde and (E)-2-hexenal were more abundant in DCA-CF. At seven days of shelf life, fermentative metabolic compounds had reduced emissions given the opening time of the chamber, while there were higher emissions of branched chain esters, especially ethyl 2-methyl butanoate in DCA-RQ1.5. The correlation was high and positive between the VCs present in the juice and those emitted by the intact fruit during seven days of shelf life, demonstrating that the concentration of VCs in juice can be used to estimate the emissions from whole fruit. DCA-RQ1.5 storage promoted the synthesis of VCs typical of the 'Fuji' apple aroma after a prolonged storage period, even under extremely low partial pressure of oxygen (average 0.15 kPa), contributing to better quality control of characteristic fruit odor and aroma.

Natural sparkling guava wine: volatile and physicochemical characterization / Espumante natural de goiaba: caracterização volátil e físico-química

ABSTRACT: Although different tropical fruit species have been used in the development of fermented beverages, there are only few references in the literature to the production of natural sparkling wines from fruits other than grapes. In this sense, the objective of the present research was the development and physicochemical and volatile characterization of a natural sparkling guava wine produced by the champenoise method. Volatile compounds were identified by gas chromatography coupled to mass spectrometry using the headspace solid-phase microextraction (HS-SPME) technique on samples. Eighty-nine volatile compounds were detected, of which 51 were identified. Esters were the predominant class of volatile compounds (a total of 26), followed by alcohols (10), terpenes (9), ketones (3), and acids (3). Volatile compounds with possible odoriferous activity were reported in the beverage, including ethyl octanoate, ethyl 5-hexenoate, phenethyl acetate, (E)-β-damascenone, (E)-ethyl cinnamate, 2-methyl butyl acetate, 3-methylbutanol, ethyl 3-(E)-hexenoate, and methyl 5-hexenoate. Natural sparkling guava wine produced showed a complex composition of fruity and floral aromas. Furthermore, the use of the champenoise method, traditionally applied to grapes, enabled the manufacture of a natural sparkling guava wine with physicochemical characteristics equivalent to those of sparkling wines made from grapes.

RESUMO: Diferentes frutos tropicais vêm sendo utilizados para o desenvolvimento de bebidas fermentadas, porém na bibliografia consultada há poucas referências sobre a produção de espumantes naturais de outras frutas diferentes da uva. Nesta perspectiva, o objetivo deste trabalho foi o desenvolvimento e a caracterização físico-química e volátil de um espumante natural de goiaba produzido pelo método champenoise. A determinação dos compostos voláteis foi realizada por cromatografia em fase gasosa acoplada a espectrometria de massas utilizando a técnica de microextração em fase sólida no headspace (HS-SPME) das amostras. Foram detectados 89 compostos voláteis, dos quais 51 foram identificados. Os ésteres foram os compostos voláteis predominantes em número, totalizando 26 compostos, seguido pelos álcoois (10), terpenos (9), cetonas (3) e ácidos (3). Compostos voláteis com possível atividade odorífera foram encontrados na bebida, dentre eles os ésteres octanoato de etila, 5-hexenoato de etila, acetato de fenetila, (E)-β-damascenona, (E)-cinamato de etila, acetato de 2-metil butila, 3-metil butanol, 3-(E)-hexenoato de etila e o 5-hexenoato de metila. O espumante natural produzido apresentou uma composição complexa de aroma frutado e floral. Além disso, a utilização do método tradicionalmente aplicado a uvas, o champenoise, proporcionou a fabricação de um espumante natural de goiaba com características físico-químicas equivalentes aos espumantes elaborados a partir de vinho.

Análise qualitativa de compostos voláteis do headspace de carne cozida de ovinos e caprinos / Qualitative analysis of headspace volatile compounds of lambs and goats cooked meat

Este estudo teve como objetivo caracterizar qualitativamente os compostos voláteis (CV) do headspace de diferentes músculos de carne cozida de ovinos e caprinos da região do Alto Camaquã, Rio Grande do Sul - Brasil. Os CV do headspace dos músculos cozidos, L. dorsi e V. lateralis de cinco ovinos machos (idade de 6 meses) e cinco cabritos machos castrados (idade de 8-9 meses) foram analisados pela técnica de microextração em fase sólida (HS-SPME) e cromatógrafo a gás acoplado a espectrômetro de massas (GC/MS). Foram encontrados 73 compostos voláteis, dentre eles aldeídos, cetonas e compostos sulfurados, característicos de carne processada termicamente. A partir da fração volátil, foi possível encontrar marcadores que discriminassem as espécies animais estudadas, caracterizando os caprinos por apresentarem, entre outros compostos, terpenos (β-pineno, α-gurjuneno, α-muuroleno), ausentes em ovinos. Alguns compostos discriminaram V. lateralis e L. dorsi de ovinos, como álcool isopropílico, α-pineno, o-xileno, porém não foi possível obter uma diferenciação entre os músculos de caprinos.

The aim of this research was to characterize qualitatively the potential markers volatile compounds of the headspace of cooked lambs and goats meat from region of Alto Camaquã, Rio Grande do Sul - Brazil. The volatile compounds of cooked meat of L. dorsi and V. lateralis muscles of five male lambs (6 months of age) and five castrated male goats (8 - 9 months of age) were analyzed by solid phase microextraction (HS-SPME) technic and gas chromatography coupled to mass spectrometer (GC/MS). Seventy-three volatile compounds were found in samples headspace, including aldehydes, ketones and sulfur compounds characteristic from processed meat. Furthermore, it was possible to discriminate goats meat mainly by identification of terpenes (β-pinene, α-gurjunene, α-muurolene), which were absent in lambs. Some compounds discriminated V. lateralis and L. dorsi lamb muscles, such as isopropyl alcohol, α-pinene, m-xylene, but there was no discrimination between the muscles of goats.