Research helps identify, by aroma, mangoes with internal collapse disorder

Researchers from five public institutions in the country took a step important to understand the so-called internal collapse, a serious problem that affects mango fruits and causes economic losses to producers and traders. O group observed that aromas and volatile compounds can serve as markers to differentiate, between healthy fruits, those that have the problem.

Known as a physiological disorder, internal collapse is responsible due to premature ripening, gelatinous appearance in the fruit pulp, darker color dark, sweeter flavor, softening under the skin and difficult to detect externally. The problem is only observed at the time of consumption, when the Fruits are generally discarded, generating waste. 

Initially based on market research and, later, on statistical models, the study identified a difference in aroma, in addition to detect, qualify and quantify a series of volatile compounds in the peel and in the fruit, which were revealed to be indicative of collapse markers internal. 

The data showed that color, firmness and volatile compounds are important to provide some information about the physiological changes caused by the disorder, which are not yet fully understood. But it's from occurrence in both the national and international markets. 

Therefore, the study by researchers from Embrapa Instrumentação (SP), University of São Paulo (USP), Federal University of São Carlos (UFSCar), São Paulo State University “Júlio de Mesquita Filho” (Unesp), with the collaboration of the Warehouses and General Warehouses São Paulo (Ceagesp), is essential to help understand the problem.

The results can support the development of identification strategies of physiological disturbance in the future, before consumption, and management to reduce fruit losses caused by collapse.

The study was conducted by agricultural engineer Fernanda Campos Alencar Oldoni to obtain her doctorate in Food and Nutrition from Unesp, Araraquara campus. According to her, the problem of internal collapse is addressed by the scientific community since the last decade.

Under the guidance of Marcos David Ferreira and co-supervision of Luiz Alberto Colnago, researchers from Embrapa, Oldoni made firstly, market research with the aim of investigating and exploring the physiological disorder through the perception of Ceagesp wholesalers. That stage identified, by aroma, that the Palmer and Tommy Atkins mango varieties are the most susceptible to physiological disorders. In experiments carried out in laboratories, with advanced analysis methods, researchers found more than 100 different volatile compounds in the fruits, of which eight are related to internal collapse.

Revealing aromas

The prospecting research was carried out with 30 Ceagesp wholesalers for through questionnaires, the answers to which helped her better understand the causes and draw a profile to characterize the internal collapse and plan the study. 

The questionnaire gathered information about wholesalers' perceptions regarding the ripening and refrigeration of the fruits, complaints about the collapse internal and percentage of disturbance in the loads sold, more subject to disturbance, in addition to possible external signs indicative of collapse and associated causal factors.

The Palmer and Tommy Atkins varieties were mentioned by 93% and 76% of the respondents, respectively, as more incidents. According to the researcher, wholesalers had the perception that the size of the fruit and fiber content could be associated with the disorder, in addition to factors external factors, such as fertilization. 

The larger size of the fruit was pointed out by 80% of those interviewed as being one of those responsible for the appearance of the collapse, while 76,7% stated that fiber content is another limiting factor.

Scientific publication

Part of the data from this work is in the article Fruit quality parameters and volatile compounds from 'Palmer' mangoes with internal breakdown, published in the journal Food Chemistry. 

In addition to Fernanda Oldoni, from the Food and Nutrition Department of Unesp, Marcos David Ferreira, Luiz Alberto Colnago and Camila Florencio, for Embrapa Instrumentação, the article is signed by Professor Stanislau Bogusz Junior and students Giovana Brait Bertazzo and Pamela Aparecida Grizotto from the Institute of Chemistry of São Carlos from the University of São Paulo (USP), and professor Renato Lajarim Carneiro from the Department of Chemistry at the Federal University of São Carlos (USFCar).

In the wholesalers' view, varieties with less fiber tend to have more breakdowns, like Tommy Atkins. But 90% of respondents believe that ripe fruits are more associated with the appearance of collapse, followed by fertilization (76,7%), soil type (50%), region of production/origin (46,7%), older plants (30%), cold storage (26,7%), hot weather (23,3%), followed by harvest season and cold weather, both representing 20% ​​of responses.

According to Oldoni, wholesalers' perception of some These factors corroborate literature studies, considering that the low calcium content, harvest delay and pre-harvest sunlight exposure may be associated with the onset of collapse. Some studies relate the disturbance with the nutritional imbalance of plants in the field. 

According to her, 93% of those interviewed said they had been notified on complaints due to collapse in commercialized cargo. The loads do not refrigerated are sold by 87% and refrigerated by 70%, according to respondents, with 31% and 54%, respectively, reporting having already presented load losses, due to collapse, exceeding 5%. 

Another fact pointed out by 27% of those interviewed is that fruits collapsed ones had a different odor. The difference in aroma between fruits with the physiological disorder and healthy fruits, it was found on-site visit at Ceagesp. 

Ferreira remembers that the scientific literature is vast on the capabilities different from humans differentiating odors, including, with implications doctors. According to international scientists, this is due to the fact that human bodies emit hundreds of volatile organic compounds which can affect personal odors.

Identification of volatiles 

Based on the survey carried out at Ceagesp, the research continued with experiments on Palmer mangoes in laboratories using advanced techniques to identify volatile compounds. The researchers started from the hypothesis that fruits with or without internal collapse had characteristics different physical and chemical composition. 

The physicochemical parameters were determined in triplicate for each sample, the researchers characterized and quantified the various compounds volatiles with the technique of gas chromatography coupled to spectrometry pasta. 

“We have identified more than a hundred different volatile compounds in the fruits. The volatiles of various mango fruits were extracted, concentrated, separated and identified, generating a huge amount of information”, says Stanislau Bogusz Junior, professor at the São Carlos Chemistry Institute (IQSC-USP). 

Chemometrics

After that, based on the results, the researchers obtained a data table with the compounds present in each fruit and their concentration relative of each one in each sleeve. Based on this result, we used multivariate data analysis technique, chemometrics, to identify which volatile compounds were capable of distinguishing a fruit with the disorder physiological among healthy people.

Chemometrics consists of the use of mathematical models, among others, for the conversion of numerical data into chemical information. Professor Renato Lajarim Carneiro from UFSCar explains that the chemometric techniques of principal component analysis (PCA) and partial least squares regression for discriminant analysis (PLS-DA).

“PCA allows us to analyze how similar the chemical profiles of volatile when comparing different fruits, that is, it makes it possible to see whether is there any obvious difference between the types of volatile compounds or even difference in the concentration of the same compound, when comparing a mango collapsed and a non-collapsed fruit. PLS-DA allows us to create a mathematical model correlating the presence of compounds and concentration between them and the internal collapse of the fruit”, explained the professor. 

According to Carneiro, this allows us to see which volatile compounds responsible for differentiating fruits with or without collapse, which makes it possible to identification of a collapsed fruit just by analyzing the exhaled compounds by the fruit. Methacrylic acid, ethyl ester, isopentenyl ethanoate, oxide of limonene, (E)-2-pentenal, tetradecane and γ-elemene are among the main volatile markers of internal collapse found in fruits. 

Oldoni concluded that the chemometric evaluation was adequate to identify the physicochemical parameters and related volatile compounds to physiological disturbance. “Fruits with internal collapse showed an increase the color index in the skin and pulp, softening of the pulp and enhancement of flavor”, reports the researcher.

Bogusz Junior explains that volatiles, like human breath, can change depending on several factors, depending on what is ingested or even according to each person's health. “In the same way, wholesome fruits and fruits with the Internal collapse will produce and eliminate different volatile compositions. A practical application of this study is fascinating, as we believe that, at some moment, we will be able to differentiate fruits with internal collapse from healthy fruits, without the need to cut, slice or open the fruits”, predicts the professor.

Furthermore, he says that future studies on biochemical pathways, that lead to the formation of these markers, can be very useful for causes of internal collapse can be known and controlled. 

Ferreira states that early identification of physiological problems internal resources contributes to directing these fruits to other purposes, rather even if they reach the consumer. According to him, this would avoid disposal, would reduce losses and waste and contribute to the rational use of resources. 

“Many of these fruits are exported or transported domestically in long distances, with unnecessary expenses for a product that will not be consumed. In this way, one can seek to increase efficiency with impacts positive for the environment, preventing them from feeding landfills, not people”, says the researcher.

Mango is the most exported Brazilian fruit

Considered a product of great nutritional and economic importance, in addition to being the most widespread crop in tropical and subtropical areas of world, the quality of the attributes of mango fruits, of Asian origin, as color, aroma, taste, flavor and texture, is of great commercial importance. From the point from a nutritional point of view, it is an excellent source of antioxidants and has significant levels beta-carotene and vitamins A and C. 

According to the Brazilian Association of Producers and Exporters of Derivative Fruits (Abrafrutas), in 2021, 270 thousand tons of mangoes were exported, the most popular Brazilian fruit shipped abroad, both in quantity and in added value, around US$248 million. The increase was 12% compared to 2020.

Mango consumption has been growing along with the demands of consumers for quality fruits. However, researcher Marcos David Ferreira recalls that the national and international market has faced different issues related to fruit management in the post-harvest. 

“The reduction in fruit quality causes significant economic losses for producers, traders, distributors and exporters, who have their diminished profits and the prestige of your product is compromised. It is also negative for consumers, who will have less product available at their table, greater prices and mangoes with lower market quality”, he states.