Evaluation of MAP engineering design parameters on quality of fresh-sliced mushrooms

The microperforated packaging design and evaluation of shelf life of fresh-sliced mushrooms

Fresh mushrooms have a very short shelf life, of 1 – 3 days because of their high respiration rate and lack of cuticles that protect the plant from external factors. In the case of fresh-sliced mushrooms, they will be more susceptible to spoilage reactions due to the increase in respiration rate as a result of a broader surface area. Conventional packaging materials can not meet the requirements for modified atmosphere packaging of fresh-sliced mushrooms. One of the techniques to extend the fresh-cut produce shelf life is the passive modification of modified atmosphere packaging technology. For highly respiring fresh-cut produce such as fresh-sliced mushrooms, the permeability properties of the polymeric materials might not be enough to provide an equilibrium gas concentration in the passive modification of modified atmosphere technology. In this case, the microperforated packaging materials can be used for passive modification of fresh-cut produce. But the microperforation process needs a design for the application of the appropriate number and diameter of microholes to meet the requirements of passive modified atmosphere packaging. For this reason in this research, the design of the microperforation process to be used in passive modified atmosphere packaging was based on the diameter and the number of microholes, and the shelf life of fresh-sliced mushrooms was determined. The samples were stored at 15 °C/80% RH, and pH, color, weight loss, textural, sensorial, and microbial analysis were performed periodically during storage. It was determined that the empirical equation used in this research can be applied to microperforated packaging design for fresh-sliced mushrooms. The shelf life of the fresh-sliced mushrooms packaged with microperforated packaging material was 8 days, while it was less than 7 days (4, 5, or 6 days) when packaged with non-microperforated packaging material. This result shows that the use of microperforated packaging material is effective in extending the shelf life of fresh-sliced mushrooms.

Investigating the effect of chitosan, nanopackaging, and modified atmosphere packaging on physical, chemical, and mechanical properties of button mushroom during storage

This study investigated the effect of chitosan coating, nanopackaging, and modified atmosphere packaging (MAP) to increase the shelf life and improve the quality of the white button mushroom. Uncoated and coated button mushrooms were stacked in three types of packages (normal, nano, and nano + MAP). The atmosphere inside the nano + MAP packages contained 10% oxygen and 10% carbon dioxide. The physical, chemical, mechanical properties and the evolution of oxygen and carbon dioxide inside the packages were investigated. The results showed that the triple interaction had significant effect (at 1% and 5% levels) on physical, mechanical properties and gas composition. The use of nanofilm (due to the low permeability to oxygen and carbon dioxide), as well as the modification of atmosphere had a positive effect on the control of mushroom respiration rate and the improvement in its physical, chemical, and mechanical properties.

Storage of Micellar Casein Powders with and without Lactose: Consequences on Color, Solubility, and Chemical Modifications

During storage, a series of changes occur for dairy powders, such as protein lactosylation and the formation of Maillard reaction products (MRPs), leading to powder browning and an increase of insoluble matter. The kinetics of protein lactosylation and MRP formation are influenced by the lactose content of the dairy powder. However, the influence of lactose in the formation of insoluble matter and its role in the underlying mechanisms is still a subject of speculation. In this study, we aim to investigate the role of lactose in the formation of insoluble matter in a more comprehensive way than the existing literature. For that, two casein powders with radically different lactose contents, standard micellar casein (MC) powder (MC1) and a lactose-free (less than 10 ppm) MC powder (MC2), were prepared and stored under controlled conditions for different periods of time. Powder browning index measurements and solubility tests on reconstituted powders were performed to study the evolution of the functional properties of MC powders during aging. Proteomic approaches [one-dimensional electrophoresis and liquid chromatography-mass spectrometry (LC-MS)] and innovative label-free quantification methods were used to track and quantify the chemical modifications occurring during the storage of the powders. Reducing the amount of lactose limited the browning of MC powders but had no effect on the loss of solubility of proteins after storage, suggesting that the action of lactose, leading to the production of MRC, does not promotes the formation of insoluble matter. Electrophoresis analysis did not reveal any links between the formation of covalent bonds between caseins and loss in solubility, regardless of the lactose content. However, LC-MS analyses have shown that different levels of chemical modifications occur during the MC powder storage, depending upon the presence of lactose. An increase of protein lactosylation and acetylation was observed for the powder with a higher lactose content, while an increase of protein deamidation and dephosphorylation was observed for that containing lower lactose. The decrease of pH in the presence of lactose as a result of Maillard reaction (MR) may explain the difference in the chemical modifications of the two powders. In view of the present results, it is clear that lactose is not a key factor promoting insolubility and for the formation of cross-links between caseins during storage. This suggests that lactosylation is not the core reaction giving rise to loss in solubility.

The effect of packaging material and storage period on microwave-dried potato (Solanum tuberosum L.) cubes

The effect of three packaging materials (transparent biaxially oriented polypropylene laminate (BOPP); semi-transparent BOPP; polyethylene-polyamide (PE-PA) laminate) in three packaging conditions (vacuum, N2, natural atmosphere) and in two temperature treatments (blanching in hot water; steam) on microwave-dried potato (Solanum tuberosum L.; Solanaceae) cubes was studied. After storage for 60 and 120 days, the amount of ascorbic acid (AA), shrinkage and rehydration were determined. Dried potato cubes packaged under N2 atmosphere had the highest rehydration value (3.142 %). Since there is a direct relationship between the amount of water loss and shrinkage, samples packaged in PE-PA laminate packages under vacuum showed 4.947 % less shrinkage than transparent BOPP or semi-transparent BOPP due to low permeability of these packages. Potatoes stored for 120 days resulted in 7.89 % more shrinkage than those stored for 60 days. The least loss in AA occurred in PE-PA laminate packaging. The shelf-life of potato cubes can be increased and their quantitative and qualitative characteristics can be best preserved by package-drying in PE-PA laminate under vacuum conditions.