Study of Alternative Packaging with Lower Environmental Impact for Fresh Yeast

Food packaging materials must meet the needs and characteristics of the product, marketing considerations, type of distribution required, environmental and waste management issues and costs. Other important factors include properties of the packaging material, such as interactions between the food and the packaging, the target market, shelf life, environmental conditions during storage and distribution, eventual disposal of the packaging and related costs. 

The search for strategies to improve the sustainability of products placed on the market has increased, especially in sectors where waste is generated and disposed of in landfills. It is essential to minimize the environmental impact caused by the consumption of fossil-based plastic packaging through innovations in the production of more sustainable plastic. The production and consumption of plastic from renewable sources is recent and offers advantages such as: soil recovery and capture of CO₂ from the atmosphere in the production process, reducing Greenhouse Gases (GHGs). 

According to ABIPLAST [1], the recycling rate is an important indicator for assessing a country's commitment to the environment. Plastic recycling has notable economic benefits and, in a 2023 study, analyzing data from the previous year, every 1 ton of recycled plastic produced generates jobs for 3.16 collectors who sort this volume of material per month. This resulted in 14,666 jobs, with 1,318 companies involved in the physical production of recycled post-consumer plastic. Recycling of post-consumer plastic represents a revenue of R$ 4 billion, which proves the economic benefits of recycling. 

Replacing fossil-based plastic with paper is another topic that has been extensively studied by the academic and the private sector on five continents. Paper, one of the first materials used for packaging, is produced from cellulose obtained from trees or even from recycled paper. It is biodegradable and recyclable, which helps preserve the environment. During processing, cellulose is treated with chemicals to bleach it and remove impurities and is then transformed into pulp and dried in a cardboard machine. 

Food loss and waste are serious and significant problems that can cause significant financial losses for companies, consumers and the environment. Currently, almost a third of all food produced in the world, around 1.3 billion tons, is sent to waste, and solutions to this problem are needed to improve packaging sustainability.

Packaging must be increasingly improved to preserve the shelf life of products and cause less environmental damage when discarded, with the choice of materials, technology, innovation, processes, equipment, design, marketing and logistics with sustainability in mind. 

In view of this, discussing the role of packaging is relevant, because it can be used in extremely creative, efficient and optimized ways to generate benefits for society and the environment. 

In this context, the present research aimed to evaluate flexible alternative packaging structures for fresh yeast, plastic and cellulose based, compared to the current structure that is composed of a regenerated cellulose film (Cellophane) coated with PVdC - poly (vinylidene chloride), which is heat-sealable. The oxygen permeability rate of this structure is 8mL (CNTP). m^-2.day^-1 a 23^oC and 1atm of oxygen partial pressure gradient and water vapor permeability rate of 20g water m^-2.day^-1 at 38°C / 90% RH. In this material, biological yeast is adequately preserved for 45 days at 1°C and 8°C and relative humidity above 80%. However, structures with PVdC present thermal instability which makes mechanical recycling difficult. 

Thus, the objective of this study was to evaluate the influence of flexible packaging structures based on plastic and cellulose with lower environmental impact on the shelf life of fresh biological yeast of the species Saccharomyces cerevisiae under two storage conditions:

• Product stored for 45 days under refrigeration at 1°C to 8°C and relative humidity above 60% - universal storage standard.
• Product stored for 30 days at a temperature of 15°C to 20°C and relative humidity above 60% - simulation of point of sale on supermarket shelves.

In the Proconor equipment, 500g yeast blocks were packaged in the types of packaging materials described in table 1. 

Table 1: Structures evaluated in this study.

Physical Analysis of Packaging 

• Grammage: determined by weighing 10x10 cm test samples of the materials, on an analytical balance with a resolution of 0.0001g in accordance with ASTM D646-96 [2,3]. 
• Total and partial thicknesses: determined according to ASTM D374-99 [4], using a dial indicator or an electronic comparator [3]. 
• Water vapor permeability rates (WVTR): determined by means of a gravimetric method, based on the ASTM E96/E96M-16 methodology [5]. 

The permeation rate of water vapor through the exposed area of each test specimen is expressed to one decimal place by Equation 1: 

Equation (1)

Where:

WVTR = water vapor permeability rate (g m^-2.day^-1)

G / t = angular coefficient of the straight line (g day^-1)

A = permeation area of the test specimen (m₂) 

When the packaging material is homogeneous and monolayer, the water vapor permeability (P) can be calculated from the permeability rate (WVTR), as indicated in Equation 2: 

Equation (2)

Where:

P = water vapor permeability (g µm m^-2 day^-1 mmHg^-1)

WVTR = water vapor permeability rate (g m^-2.day^-1)

e = average thickness of the test specimen (µm)

ps = vapor saturation pressure at the test temperature (mmHg)

UR1 = relative humidity of the chamber

UR2 = relative humidity inside the capsule

• Oxygen Permeability (OTR): The oxygen permeability rates of the samples were determined according to ASTM D3985-17 [6], using OXTRAN equipment from MOCON. 

The oxygen permeability rate is given directly by the equipment reading. The oxygen permeability coefficient (P) can be calculated using Equation 3:

Equation (3)

Where:

P = permeability coefficient

OTR = oxygen permeability rate (mL m^-2 day^-1)

e = film thickness (µm)

p = partial pressure of oxygen in the test chamber (atm), since the partial pressure of O₂ in the carrier gas chamber is assumed to be zero

Physical-Chemical Analysis of Product x Packaging 

The evaluations performed on the yeast during the shelf-life study under the two storage conditions were:

• Weight: The products (packaging + product) were weighed using a semi- analytical scale, Mettler Toledo brand, model PB5001. The value was expressed in grams (g) and at the end the variation in weight of the products between the structures analyzed was evaluated.
• Friability: This analysis evaluates the capacity of a material to disintegrate when subjected to mechanical stress or vibrations. It is a visual analysis that consists of manually breaking up a yeast sample and evaluating the ease of crumbling on a scale of 1 to 5, where:

1. – forms dough,
2. – forms balls,
3. – forms lumps,
4. – forms small lumps and
5. – crumbles

• This evaluation was subjective and is part of the customer's perception. The expected result for this test is a friable product that crumbles well when rubbed, hence a score of 5. 
• Determination of Dry Matter (Solids%): Performed using the Conventional Method using a forced air oven, after weighing 1.5g to 2.0g of the sample, it was stored in an oven at 105°C for 24h. The solids or moisture are calculated by difference in weight [7]. 
• Fermentative Power - Short Fermentation: The materials and methods used in this test are found in AACC [8]. Method capable of determining the total volume of CO₂ gas produced by the yeast during storage, performed in Risograph equipment (30ºC for 2 hours). The amount of sugar can directly influence the results obtained; ideally, formulations with 0% b.f. and 18% b.f. of sugar should be used. In order to obtain representative results, a standard was maintained in the formulations tested [8-11]. 
• Fermentative Power - Shelf Stress Test: Method designed to measure yeast resistance to stress during its shelf life, performed in a Risograph (30°C for 4 hours) using the formulations presented in table 2. It is a way of simulating the different market conditions to which yeast may be exposed. In this study, the yeast was stored at a controlled temperature between 1 and 8°C and relative humidity between 65% and 75%, with only the packaging material being variable.

Table 2: Shelf stress test formulations.

The shelf stress analysis results are obtained by using Equation 5, compared to the first day of study (Day00).

Equation (5)

Where:

Day00 = Day on which the initial shelf stress test was performed

XX = Number of calendar days on which the shelf stress test was performed after Day00

AEPXX = Stress test result on DayXX (%)

MEDXX = Arithmetic mean of carbon dioxide produced by shelf stress tests 1, 2, 3 and 4 on DayXX (mL CO₂/4h)

MED00 = Arithmetic mean of carbon dioxide produced by shelf stress tests 1, 2, 3 and 4 on Day00 (mL CO2/4h)

Physical Analysis of Packaging 

• Grammage Assessment (g/m²): Table 3 shows that the grammage of the Uncoated Cellophane structure studied was lower than the Standard structure, due to the lack of internal and external coating, and is an option with lower packaging consumption. However, the grammages of the Paper/PLA, Paper/LDPE and Monolucid Paper/TS structures were higher than the Standard structure and, therefore, are options with higher packaging consumption.

Table 3: Grammage assessment (g/m²). 

• Thickness Assessment (µm): Table 4 shows that the thickness of the Uncoated Cellophane structure studied was smaller than that of the Standard structure, due to the lack of internal and external coating, making it an option with lower packaging consumption. The thickness of the Paper/PLA, Paper/LDPE and Monolucid Paper/TS structures are greater than those of the Standard structure. Therefore, it is an option with higher packaging consumption.

Table 4: Thickness Assessment (µm). 

In order to assess the impact on packaging consumption, we considered the following information:

• Annual consumption of 100 tons of packaging;
• Total grammage and thickness of the structures evaluated and reported in tables 3 & 4;
• 500g packaging with 285mm pitch and 200mm 

Therefore, according to the data presented in table 5, packaging consumption in the Uncoated Cellophane structure is 7% less than consumption in the Standard structure, an annual reduction in consumption of approximately 6.9 tons of packaging. Consumption in the other structures was higher, being 117% more in the Paper/PLA structure, an annual increase of 116.7 tons of packaging, 79% more in the Paper/LDPE structure, an annual increase of 79.2 tons of packaging and 51% more in the Monolucid Paper/TS structure, an annual increase of 51.4 tons of packaging.

Table 5: Consumption assessment of packaging structures. 

Another factor that could be assessed in this study based on the consumption and volume of the structures was cost and availability.

Again, let's consider the following data:

• Annual consumption of 100 tons of packaging;
• Total grammage and thicknesses of the evaluated structures reported in tables 3 & 4; 

As shown in table 6, we can conclude that even with weights and thickness well above the Standard structure, the Paper/LDPE and Monolucid Paper/TS structures presented a much higher annual cost reduction than the other structures evaluated. This is due to the high production availability of these structures, making the cost more competitive and attractive. The Uncoated Cellophane structure also presented a cost reduction, but due to the reduction in consumption of this structure. However, the Paper/PLA structure, in addition to having presented high packaging consumption due to its weight, demonstrates low production availability, still being a high-cost structure for companies.

Table 6: Cost assessment of packaging structures.

• Water Vapor Permeability Rates Assessment (WVTR): In table 7, the WVTR results indicate that the Uncoated Cellophane, Paper/LDPE and Monolucid Paper/TS structures have excellent water vapor barrier characteristics, superior to the parameters presented by the Standard structure. 

However, the Paper/PLA structure presented a higher water vapor permeability rate than the Standard (lower water vapor barrier), which caused a loss of friability after 25 days of shelf-life study and the result obtained was below the recommended one.

Table 7: WVTR - Water Vapor Permeability Rates at 38ºC / 90% RH. 

Note: Values referring to two determinations

M: Mean; VR: Variation Range; CV: Coefficient of Variation

Oxygen Permeability Rates Assessment (OTR): The OTR results described in table 8, demonstrate that the Uncoated Cellophane structure presents oxygen barrier characteristics close to those of the Standard and the oxygen barrier of the Monolucid Paper/TS was slightly superior. 

The Paper/PLA and Paper/LDPE structures presented oxygen permeability superior to that of the Standard, therefore with low or no oxygen barrier characteristics, which caused a shorter shelf life of the yeast and caused a loss of fermentative power and % of solids after 35 days of the study. 

Table 8: OTR - Oxygen Permeability Rates at 23°C dry and 1atm oxygen partial pressure gradient. 

Note: Values referring to three determinations

M: Mean; VR: Variation Range; CV: Coefficient of Variation

Although the oxygen permeability rate is usually expressed in mL (CNTP). m^-2.day^-1, no international system of units is expressed in mol. m^-2.s ^-1, where 1mL(CNTP) is equivalent to 44.62µmol and 1 day is 86.4x103s

Physical-chemical Analysis Product x Packaging: Stored under refrigeration at 1°C to 8°C for 45 days Weight (g) 

The weight results presented in figure 1, indicate lower weight loss of the yeast in the Paper/LDPE, Uncoated Cellophane and Paper/PLA structures compared to the product in the Standard structure. 

The yeast in the Monolucid Paper/TS structure presented greater weight loss compared to the product in the Standard structure because this structure presented greater permeability to water vapor.

 Figure 1: Weight variation analysis (g) - day 1 to day 45.

• Friability: It was observed that the yeast friability in the Uncoated Cellophane structure was similar to that of the product in the Standard packaging (Figure 2), indicating that there was no difference in relation to product degradation during the study in the two structures. 

In the Paper/PLA, Paper/LDPE and Monolucid Paper/TS structures, the yeast friability was lower than that obtained in the Standard structure, demonstrating signs of a doughy product, without any friable aspect.

 Figure 2: Friability – day 1 to day 45.

• Determination of Dry Matter (Solids %): In figure 3, the results of dry matter quantified in the yeast in the Uncoated Cellophane and Paper/PLA structures were similar to those quantified in the Standard structure, indicating similar degradation in these materials to that of the product in Standard packaging. 

The dry matter quantified in the yeast in the Paper/LDPE and Monolucid Paper/TS structures indicated a similar or slightly lower result when compared to the standard, demonstrating similar degradation in these options to that of the product in the Standard packaging.

 Figure 3: Determination of dry matter (solids %) - day 1 to day 45.

• Fermentative Power for 0% b.f. Sugar: Figures 4 & 5, show the volumes of CO₂ produced on days 1 and 45 and the relative percentages of the volumes of CO₂ produced on days 1 and 45, respectively. It was observed that the yeast in the Uncoated Cellophane structure presented the lowest loss of fermentative power during the shelf-life study, when compared to the Standard structure. 

The yeast in the other structures: Paper/LDPE, Paper/PLA and Monolucid Paper/TS presented greater loss of fermentative power during the shelf-life study, when compared to the Standard structure. Therefore, there was an imbalance between water loss and the release of carbon dioxide.

 Figure 4: Fermentative power (0% b.f. sugar) - day 1 to day 45.

 Figure 5: Fermentative power (0%b.f. sugar - %) - day 1 to day 45.

• Fermentative Power for 18% b.f. Sugar: Figures 6 & 7, show the volumes of CO₂ produced on days 1 and 45 and the relative percentages of the volumes of CO₂ produced on days 1 and 45, respectively. It was found that in the evaluation with 18% b.f. sugar, the yeast in the Uncoated Cellophane structure presented a superior result than the product in the Standard structure. Therefore, in this evaluation there was no imbalance between water loss and carbon dioxide release.

In the evaluation with 18% b.f. sugar, the yeast in the Paper/PLA, Paper/LDPE, Monolucid Paper/TS structures presented an inferior result than the product in the standard structure. Therefore, in this evaluation there was an imbalance between water loss and carbon dioxide release, indicating that the product did not maintain adequate fermentative power in these structures.

 Figure 6: Fermentative power (18% b.f. sugar) - day 1 to day 45.

 Figure 7: Fermentative power (18% b.f. sugar - %) - day 1 to day 45.

• Product Fermentation Power – Shelf Stress Test: Figure 8, shows the fermentation power, where the yeast in the Paper/PLA, Uncoated Cellophane, Paper/LDPE and Monolucid Paper/TS structures lost fermentation power during the shelf life, compared to the product in the Standard structure. 

In these structure options, the yeast would show a smaller oven jump on day 45 in the established recipes.

Figure 8: Fermentation potency – shelf stress test – day 1 to day 45.

Physical-chemical Analysis Product x Packaging: Stored at a temperature of 15°C to 20°C for 30 days Weight (g)

The results obtained were similar to the evaluations at temperatures of 1°C to 8°C for 45 days. 

In figure 9, it can be seen that the yeast weight results in the Paper/LDPE, Uncoated Cellophane and Paper/PLA structures were superior/similar in relation to weight loss when compared to the Standard. 

The Monolucid Paper/TS structure showed greater weight loss when compared to the Standard, due to the high-water vapor permeability rate of this structure.

Figure 9: Weight variation analysis (g) - day 1 to day 30.

• Friability: The results obtained were similar to those of the evaluations at temperatures of 1°C to 8°C for 45 days. In figure 10, it can be seen that the friability of the yeast in the Uncoated Cellophane structure was similar to that of the product in the Standard packaging, therefore there was no difference in relation to the degradation of the product during the study in the two structures. 

In the Paper/PLA, Paper/LDPE and Monolucid Paper/TS structures, the friability of the yeast was lower than that of the product in the standard structure, demonstrating signs of a doughy product, without any friable aspect with greater degradation.

 Figure 10: Friability – day 1 to day 30.

• Determination of Dry Matter (Solids %): In figure 11, the dry matter results, under these temperature and time conditions, showed a difference in the dry matter of the yeast in Paper/PLA and Monolucid Paper/TS, inverting the results observed in the evaluations at 1°C and 8°C for 45 days. 

However, the results of the yeast in Uncoated Cellophane and Paper/LDPE structures were similar to those of the evaluations at 1°C and 8°C for 45 days.

 Figure 11: Determination of dry matter (solids %) - day 1 to day 30.

• Fermentative Power for 0% b.f. Sugar: The results obtained were similar to those of the evaluations at temperatures of 1°C to 8°C for 45 days. Figures 12 & 13, show the volumes of CO₂ produced on days 1 and 45 and the relative percentages of the volumes of CO₂ produced on days 1 and 45, respectively. It was observed that in the Uncoated Cellophane structure there was less loss of fermentative power of the yeast during the shelf-life study, when compared to the Standard structure. Therefore, there was a slight imbalance between water loss and the release of carbon dioxide. 

In the other structures: Paper/LDPE, Paper/PLA and Monolucid Paper/TS, the yeast showed greater loss of fermentative power during the shelf-life study, when compared to the Standard structure. Therefore, there was an imbalance between water loss and the release of carbon dioxide. In this study, it is possible to observe that even with a greater quantity of dry matter in the yeast, the product in these structures did not maintain adequate fermentative power.

 Figure 12: Fermentative power (0% b.f. sugar) - day 1 to day 30.

 Figure 13: Fermentative power (0%b.f. sugar - %) - day 1 to day 30.

Fermentative Power for 18% b.f. Sugar: The results obtained were similar to those of the evaluations at temperatures of 1°C to 8°C for 45 days. Figures 14 & 15, show the volumes of CO₂ produced on days 1 and 45 and the relative percentages of the volumes of CO₂ produced on days 1 and 45, respectively. It was found that in the evaluation, with 18% b.f. sugar, the yeast in the Uncoated Cellophane structure presented a slightly higher result than the product in the Standard structure. Therefore, in this evaluation there was no imbalance between water loss and carbon dioxide release. 

In the evaluation with 18% b.f. sugar, the yeast in the Paper/PLA, Paper/LDPE, Monolucid Paper/TS structures presented a lower result than the product in the Standard structure. Therefore, in this evaluation there was an imbalance between water loss and carbon dioxide release, indicating that the product in these structures did not maintain adequate fermentative power. 

 Figure 14: Fermentative power (18% b.f. sugar) - day 1 to day 30.

 Figure 15: Fermentative power (18% b.f. sugar - %) - day 1 to day 30.

Among the packaging materials evaluated are provided that:

Uncoated Cellophane 

• Structure: Regarding the structure, it presents good sustainability requirements, being produced from a renewable source and 100% compostable. The material does not contain any coating that impairs recyclability or compostability. 

It has a lower grammage than the standard structure, therefore reducing packaging material consumption by approximately 7%. 

Because it presents WVTR and OTR similar to the Standard structure, it presented excellent results in the physical-chemical parameters evaluated in the fresh biological yeast in this option, maintaining the quality of the fresh yeast throughout the life cycle. 

• Assessment for 45 Days and Temperature of 1°C to 8°C: Regarding weight loss, the Uncoated Cellophane structure presented better performance, having a weight reduction during the study, smaller when compared to the standard structure. 

Regarding friability and dry matter determination, the Uncoated Cellophane structure presented similar results and performance to the product in the Standard packaging, therefore there was no difference in relation to product degradation during the study in the structures. 

Regarding the fermentative power with 0% b.f. Sugar and 18% b.f. Sugar, we observed a difference between the results. With the fermentative power of 0% b.f. sugar, the yeast in the Uncoated Cellophane structure showed a tendency to lose fermentative power during the study, in this case there was a slight imbalance between water loss and carbon dioxide release. In the evaluation with 18% b.f. sugar, the yeast in the Uncoated Cellophane structure presented a slightly superior result than the standard structure, in this case there was no imbalance between water loss and carbon dioxide release. 

Regarding fermentative power, the yeast in the Uncoated Cellophane structure lost fermentative power and took longer to reach the oven jump of the established recipes. 

• Assessment for 30 Days and Temperature of 15°C to 20°C: In relation to weight loss, friability, determination of dry matter and fermentative power 0% b.f. Sugar and 18% b.f. sugar, we had the same results obtained in the evaluations at temperature of 1°C to 8°C for 45 days. 

Therefore, with the results obtained, we can conclude that the Uncoated Cellophane structure meets the quality and protection requirements that the product needs, presenting similar and superior results to those of the standard structure.

Paper/PLA 

• Structure: Regarding the structure, it presents good sustainability requirements, produced from a renewable/bio-based source and 100% compostable. The material does not contain any coating that impairs recyclability or compostability. 

It has a higher grammage than the standard structure, therefore a significant increase of approximately 117% in packaging consumption. 

Due to the medium/low barrier to OTR and WVTR, the physical-chemical parameters of the biological yeast in this structure showed a reduction in quality characteristics during the shelf-life study. 

• Assessment for 45 Days and Temperature of 1°C to 8°C: Regarding weight loss, the Paper/PLA structure showed better performance in terms of weight reduction during the study when compared to the standard structure. 

Regarding friability, the Paper/PLA structure presented results and performance inferior to the product in the standard packaging, demonstrating signs of product degradation, however, in relation to the determination of dry matter, the Paper/PLA structure presented results and performance superior to the product in the standard packaging, therefore the yeast presented degradation inferior to the product in the standard packaging. 

However, in the fermentation power assessments with 0% b.f. Sugar and 18% b.f. Sugar, we observed a difference between the results. The yeast showed a loss of fermentation power during the study and, therefore, there was an imbalance between water loss and carbon dioxide release. In this study, it is possible to observe that even with a greater amount of dry matter in the yeast, the product, in the Paper/PLA structure, was unable to maintain adequate fermentation power, causing the yeast to take longer to reach the oven jump of the established recipes. 

• Assessment for 30 Days and Temperature of 15°C to 20°C: In relation to weight loss, friability, determination of dry matter, and fermentation power 0% b.f. Sugar and 18% b.f. Sugar, we had the same results obtained in the assessments at temperatures of 1°C to 8°C for 45 days. 

Therefore, with the results obtained, we can conclude that the Paper/PLA structure does not meet the safety, quality and protection requirements that the product needs, presenting inferior results to the standard structure.

Paper/LDPE 

• Structure: Regarding the structure, it does not have good sustainability requirements, produced from renewable/fossil sources (paper base and plastic base), which cannot be recycled in the paper or plastic chain. 

It has a higher grammage than the standard structure, therefore a significant increase of approximately 79% in packaging consumption. 

Due to the average barrier to WVTR and no barrier to OTR, in this structure the yeast showed a reduction in one of its main quality characteristics (fermentative power). 

• Assessment for 45 Days and Temperature of 1°C to 8°C: Regarding weight loss, the Paper/LDPE structure showed better performance, with a weight reduction during the study, lower when compared to the standard structure. 

Regarding friability, the Paper/LDPE structure presented results and performance inferior to the product in standard packaging, demonstrating signs of product degradation. However, in relation to the determination of dry matter, the Paper/LDPE structure presented results and performance similar to the product in the standard packaging, therefore the yeast presented degradation similar to the product in the standard packaging. 

However, in the fermentation power assessments with 0% b.f. Sugar and 18% b.f. Sugar, we observed a difference between the results. The yeast showed a loss of fermentation power during the study and, therefore, there was a certain imbalance between water loss and carbon dioxide release. In this study, it is possible to observe that even with a greater amount of dry matter in the yeast, the product, in the Paper/LDPE structure, was not able to maintain adequate fermentation power, causing the yeast to take a little longer to reach the oven jump of the established recipes. 

• Assessment for 30 Days and Temperature of 15°C to 20°C: In relation to weight loss, friability, determination of dry matter, and fermentation power 0% b.f. Sugar and 18% b.f. Sugar, we had the same results obtained in the assessments at temperatures of 1°C to 8°C for 45 days. 

Therefore, with the results obtained, we can conclude that the Paper/LDPE structure had difficulty in meeting the safety, quality and protection requirements that the product needs, presenting inferior results to the standard structure. 

Monolucid Paper/TS 

• Structure: Regarding the structure, it presents good sustainability requirements, produced from a renewable source and 100% recyclable. 

It has a higher grammage than the standard structure, therefore a significant increase of approximately 51% in packaging consumption. 

Due to the high permeability rates of water vapor and oxygen, no physical-chemical parameters of the product were preserved in this structure throughout the shelf-life study, since the biological yeast presented a loss of all quality characteristics during the shelf-life study. 

• Assessment for 45 Days and Temperature of 1°C to 8°C: Regarding weight loss, the Monolucid Paper/TS structure presented the greatest weight loss, when compared to the standard, due to the high permeability of the structure. 

Regarding friability, the Monolucid Paper/TS structure presented results and performance inferior to the product in the standard packaging, demonstrating signs of product degradation, however, in relation to the determination of dry matter, the Monolucid Paper/TS structure presented results and performance similar to the product in the standard packaging, therefore the yeast presented degradation similar to the product in the standard packaging. 

However, in the fermentation power assessments with 0% b.f. Sugar and 18% b.f. Sugar, we observed a difference between the results. The yeast showed a significant loss of fermentation power during the study and, therefore, there was an imbalance between water loss and carbon dioxide release. In this study, it is possible to observe that even with a greater amount of dry matter in the yeast, the product, in the Monolucid Paper/TS structure, was unable to maintain adequate fermentation power, causing the yeast to take longer to reach the oven jump of the established recipes. 

• Assessment for 30 Days and Temperature of 15°C to 20°C: In relation to weight loss, friability, determination of dry matter and fermentation power 0% b.f. Sugar and 18% b.f. Sugar, we had the same results obtained in the assessments at temperatures of 1°C to 8°C for 45 days. 

Therefore, with the results obtained, we can conclude that the Monolucid Paper/TS structure did not meet the safety, quality and protection requirements that the product needs, presenting results inferior to those of the standard structure.

This study aimed to evaluate the effect of different flexible packaging structures based on plastic and cellulose, with lower environmental impact, on the stability of the fresh biological yeast product of the species Saccharomyces cerevisiae during the shelf life under two conditions. 

It was possible to conclude that even without any coating, the Uncoated Cellophane structure presented similar results and, in some tests, superior to the Standard structure, meeting the physical-chemical and sustainability requirements. The product presented lower weight loss and excellent friability, lower degradation and superior fermentative power when compared to Standard, better preserving the cell, thus creating a balance between cell loss and the release of carbon dioxide and water. 

The excellent barrier to water vapor and oxygen allowed product quality throughout the shelf-life study. 

The Paper/LDPE structure continues to be a good option for studies, as it has shown good technical viability, however, some adjustments will be necessary in relation to the oxygen permeability rate and recyclability. In this structure, the product showed little weight loss, low friability and little loss of dry matter, which interfered with the fermentative power, accelerating the cell metabolism. 

The Paper/PLA and Monolucid Paper/TS structures, on the other hand, did not show good technical viability, as they presented losses of the main product quality parameters during the shelf-life study. 

The low barrier to water vapor and oxygen in the packaging contributed to the loss of product quality throughout the shelf-life study. As for future studies, it would be interesting to carry out improvements in the Paper/LDPE structure and new analyses with similar studies, in addition to larger-scale tests with the Cellophane structure without coating for market evaluation.

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