Shelf-life Experiments Research Articles

The pasture system improves natural antioxidants and functional lipids while reducing lipid peroxidation in Ctenopharyngodon idella (grass carp) burgers during storage

C. idella burgers made from a pasture-based system provide a natural method for producing high-quality fish products, resulting in meat enriched with polyunsaturated fatty acids, particularly EPA and DHA, as well as fat-soluble vitamins and antioxidants. In this study, C. idella meat burgers were made from two types of diets: pasture-based (PS) and grain-based (GS). A total of 36 burgers were stored in plastic trays (three burgers per tray; 12 trays per group), in a refrigeration chamber at 4 °C ± 0.1 °C for 120 h to conduct a shelf-life experiment comparing the meats. Initial fatty acid profile and nutritional composition were determined at 0 h. Additionally, fat-soluble vitamins, antioxidants, TBA, and FRAP were measured at 0, 24, 48, 72, 96, and 120 h. PS burgers exhibited higher concentrations of n-3 LC-PUFAs, vitamins, antioxidants, except for gamma-tocopherol, and FRAP than GS burgers (P < 0.05), while GS burgers had higher TBA and γ-tocopherol (P < 0.05). Both burgers experienced vitamin reduction during storage, with PS burgers maintaining higher concentrations. Vitamin decline correlated with increased oxidation (TBA) in both burger types. These results suggest that pasture-fed burgers have longer shelf life than GS burgers due to reduced oxidation and enhanced stability of bioactive compounds.

Physicochemical- and bioactive properties of acid preserved Alaria esculenta and Saccharina latissima during storage

The short harvesting period of cultivated brown seaweed in Europe can make it difficult for cultivators to produce high quality seaweed biomass all year around. Hence there is a need for novel processing and preservation methods. Acid preservation is a well-known method to preserve food, where the aim is to reduce the pH below 4.5 to inhibit microbial growth. To evaluate the effectiveness of acid preservation, a shelf-life experiment was conducted with Saccharina latissima and Alaria esculenta. The biomass was either treated with lactic- or citric acid and stored for approximately seven months. Physicochemical (including proximate composition, trace minerals, total phenolic content (TPC), texture and pH), microbial-, sensory attributes, and antioxidant (ORAC, DPPH) analyses were performed on the preserved biomass during storage. The proximate composition, color, pH, and texture of the acid-preserved seaweed were relatively stable throughout the storage. However, a decrease was observed in TPC and antioxidant properties (assessed by DPPH) with the acid treatments. Acid preservation is, thus, a good method to stabilize the studied biomass for food and feed applications but less applicable if intended for antioxidant purposes. However, the acid treated biomass might be suitable as an ingredient for a wide range of value-added products.

Re-formulating Monascus fermented durian seeds yogurt with strawberry (Fragaria x ananassa) puree to enhance its microbiological, physicochemical and organoleptic properties

Healthy lifestyle and consumption of fermented products, is the trend that is popular among health-conscious individuals. Monascus fermented durian seed (MFDS) is a fermented product of durian seed using the Monascus purpureus culture. Even though MFDS possessed specific bioactive properties, such as competent antioxidant, antidiabetes and anti-hypercholesterolemia. However, the addition of MFDS extract to yogurt has some limitations [e.g.: reduction of colour and taste preference]. Thus, there is a need for an innovative food technology method to enhance key organoleptic characteristics of a newly formulated yogurt product made of MFDS and strawberry puree. The aim of this investigation was to determine the effect of difference concentrations of strawberry puree on microbiology, physicochemical, and organoleptic properties of MFDS yogurt product. The results showed that all concentrations of strawberry puree [5%, 10%, 15%, and 20% (w/v) of the total mixture] have affected the microbial, physicochemical and sensory properties of re-formulated yogurt product. Strawberry purees caused an acidity increase of yogurt with pH value between 4.287 and 4.475. The recorded titratable acidity was 0.74% to 1.17%. The colour parameters such as lightness and yellowness also decreased, however, the values of redness, chroma, and hue increased. The shelf-life experiment (maximum of 7 days) of the re-formulated yogurt revealed a maximum syneresis of 22.52%. Based on the sensory evaluation preferences, re-formulated yogurt with 10% strawberry puree was the most favourable product, with a preferred value of the colour at 5.6 (rather like), the flavour at 5.8 (rather like), and mouthfeel (rather like).

Remaining Shelf-Life Estimation of Fresh Fruits and Vegetables During Transportation

During transportation, prediction of the Remaining Shelf-Life (RSL) of Fresh Fruits and Vegetables (FFVs) is critical for planning and quality cost estimation. The Internet of Things (IoT) enables measured environmental variables to be processed in real-time. However, there is a need for a validated, real-time computational method that translates environmental measurements to dynamic RSL estimates. Most existing generic RSL models for FFVs are qualitative, invasive, or static. This study establishes a generic RSL model for FFVs under dynamic and unplanned logistic conditions. The model is based on estimating the current rate of general decay based on the expected respiration rate of the product, and integrating the decay rate with respect to time. Its implementation is non-destructive, non-invasive, and does not require accelerated shelf-life experiments before deployment. In addition, since the original model is rather computationally intensive, a surrogate model was proposed to allow the model to be implemented in fast, real-time applications for ‘Edge IoT.’ Experimental validation of the model using three fresh products (strawberries, apricots, and spinach) in a domestic refrigerator resulted in a maximum deviation of 1.3 days in prediction error using the original model and 2.95 days using the surrogate model. Nonetheless, the predictions made using either the original or surrogate models were statistically sound and not significantly different from the observed shelf lives of the samples, even at the 0.01 significance level.

Building “First Expire, First Out” models to predict food losses at retail due to cold chain disruption in the last mile

Current less-than-truckload (LTL) shipping practices allow for temperature abuse (TA) in the last segment (last mile) of the food supply chain. When this TA is combined with “First In, First Out” product rotation methods, it could lead to food spoilage and food waste; therefore, data-based decision models are needed to aid retail managers. An experiment was designed using pallets (4 layers/pallet × 5 boxes/layer) of commercially produced boneless chicken breast filet trays. The pallets were exposed to 24 h of simulated LTL TA (cyclic 2 h at 4°C, then 2 h at 23 ± 2°C). Filet temperatures were recorded for all 20 boxes using dataloggers with thermocouple wires. Additionally, microbiological sampling of filets [aerobic plate counts (APC) and psychrotrophic plate counts (PSY)] was conducted before (0 h of LTL TA) and after (24 h of LTL TA) the TA experiment for select boxes of the pallet and compared to control filets (maintained at 4°C). After TA, a shelf-life experiment was conducted by storing filets from predetermined boxes at 4°C until spoilage (7 log CFU/ml). Temperature and microbiological data were augmented using Monte Carlo simulations (MC) to build decision making models using two methods; (1) the risk of each box on the pallet reaching the bacterial “danger zone” (&amp;gt;4°C) was determined; and (2) the risk-of-loss (shelf-life &amp;lt; 4 days; minimum shelf-life required to prevent food waste) was determined. Temperature results indicated that boxes on the top and bottom layers reached 4°C faster than boxes comprising the middle layers while the perimeter boxes of each layer reached 4°C faster than centrally located boxes. Shelf-life results indicate simulated LTL TA reduced shelf-life by 2.25 and 1.5 days for APC and PSY, respectively. The first MC method showed the average risk of boxes reaching 4°C after 24 h of simulated LTL TA were 94.96%, 43.20%, 27.20%, and 75.12% for layers 1–4, respectively. The second MC method indicated that exposure at &amp;gt;4°C for 8 h results in a risk-of-loss of 43.8%. The findings indicate that LTL TA decreases shelf-life of chicken breast filets in a heterogenous manner according to location of boxes on the pallet. Therefore, predictive models are needed to make objective decisions so that a “First Expire, First Out” method can be implemented to reduce food wastes due to TA during the last mile.

Proteomic analysis of antifungal mechanism of star anise essential oil against Aspergillus niger and its application potential in prolonging bread shelf life

In this paper, the main chemical constituents of star anise essential oil (AEO) were analyzed. Then the antifungal mechanism of AEO against Aspergillus niger was investigated by proteomics and its application potential in prolonging the shelf life of bread was analyzed. à-Guaiene was the highest content in AEO, followed by Azulene and Terpinen-4-ol. AEO can reduce the ATP content and cell viability of A. niger. A total of 283 protein remarkable expressions of A. niger after AEO treatment were found through protein omics. Further analysis showed that these differentially expressed proteins were mainly concentrated in the energy metabolism system of A. niger. AEO inhibits the growth of A. niger by blocking the synthetic pathway of NAD. In addition, A. niger activated additional energy production pathways, such as glycan metabolism, to compensate for its lack of energy after AEO treatment. Finally, shelf-life experiments showed that AEO extended the shelf life of bread to day 8. These results suggested that AEO can be used as an antifungal agent to prolong the shelf life of bread.

Study on the Composition and Physiological Activity of the Essential Oils and Extracts of Cinnamomum camphora Fruit.

Supercritical carbon dioxide (SC-CO2 ), hydrodistillation (HDO), ethanol extraction (EE), and petroleum ether extraction (PE) were used to extract the essential oil and extracts of Cinnamomum camphora fruit in this study. Gas chromatography-mass spectrometry was used to identify the volatile components of essential oils and extracts, and 63 compounds were identified. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay and Ferric reducing ability of plasma (FRAP) assays and the inhibition experiment of bacteria and fungi (Staphylococcus aureus (S. aureus), Hay bacillus (H. bacillus), Escherichia coli (E. coli), Aspergillus niger (A. niger), Candida albicans (C. albicans)) showed these essential oils and extracts indicated antioxidant and antibacterial activities. S. aureus was the most sensitive to the essential oil (MIC=0.08 mg/ml). Combined with the Brine Shrimp Lethality Test (BSLT) experiment, HDO (LD50 =68.21 μg/ml) was considered to have the most potential natural preservative. Subsequently, the inhibitory mechanism of HDO on bacteria and fungi was explored through extracellular conductivity and SEM, and the possibility of HDO to preserve the freshness of bananas was verified through banana shelf-life experiments. The results suggested these essential oils and extracts of Cinnamomum camphora fruit indicated effectively inhibit the growth of microorganisms on the surface of bananas, extend the shelf-life, and have the potential to become a natural antiseptic ingredient.

Paper-Based Microfluidic Devices: Low-Cost Platforms for Rapid Biochemical Detection.

We developed low-cost, portable paper-based diagnostic devices for detection of human immunoglobulin M (IgM) and immunoglobulin G (IgG) in serum without any sample preparation. These devices can be used to help identify presence of diseases, used to provide rapid results (<5 minutes), readily used by untrained personnel, employed in austere environments, configured to obtain multiplexed assays, and easily disposed of. We successfully accomplished colorimetric detection of human IgG and human IgM using a sandwich-style assay within the microfluidic paper device via vertical flow immunoassay configuration. The reaction zone in the wax printed paper layer is a small circular pattern. Gold nanoparticles conjugated with anti-human IgG and IgM antibodies have been used for colorimetric detection of IgG or IgM by naked eye. Colorimetric signal can be precisely quantified through implementation of image analysis software which can be developed as an app for a smartphone. The size of the device is 2 cm × 2 cm × 1 mm. Colorimetric detection of human IgG was accomplished at 100 fg/mL concentration using a gold nanoparticle-conjugated anti-human IgG antibody. The developed platform has a dynamic range of IgM and IgG concentrations between 0.1 pg/mL and 100 μg/mL. These devices provided a color readout in <5 minutes using 20 µL of serum. We also demonstrated that the devices show a significant degree of ruggedness and temperature stability as they were able to provide satisfactory results (detection of 0.1 pg/mL IgG) after 14 days of long stability and shelf-life experiment at an elevated temperature of at least 50 ˚C-the shelf life can be as long as 180 days under ambient conditions for detection of 100 µg/mL IgG. Because of the inherent simplicity of the device operation and their ease of use, there is no variation between samples and users of the device. This low-cost approach enables multiplexing with >1 measurement performed in parallel at the same time. We anticipate that because of the sensitivity, specificity, ease of use, and overall reliability, this approach will become a standard for diagnosis of diseases and health conditions.

Isolation, identification and thermal inactivation of dominant spoilage bacteria in egg curds

The egg curd is one of the most promising ready-to-eat egg products in China, which can greatly enhance the commercial value of eggs. At present, there are few studies on the spoilage bacteria of egg curds and the suitable heat treatment condition remains obscure. This study isolated and identified the spoilage bacteria from egg curds and then determined a suitable heat treatment condition. Bacillus velezensis EC 1 and Bacillus cereus EC 2 were isolated from spoiled products. The B. velezensis EC 1 spore was more thermal resistant than B. velezensis EC 1. The D90, D95 and D100 values of B. cereus EC 2 spores were 7.97, 2.23 and 0.93 min respectively, while the values of B. velezensis EC 1 spores were 26.87, 6.80 and 2.18 min, respectively. Based on the above D-values, we designed several heat treatment intensities and evaluated the heat treatment effect through shelf-life experiment. The egg curds heated at 100 °C for 10 min could maintain microbial safety during the 180-day storage period and the pH, total volatile basic nitrogen and thiobarbituric acid reactive substances values were relatively more stable. Therefore, in this study, the most suitable heat treatment condition for egg curds is 100 °C, 10 min. These findings will provide realistic guidance for egg curd manufacturers.

Vitamin B12 determination in milk, whey and different by-products of ricotta cheese production by ultra performance liquid chromatography coupled with tandem mass spectrometry.

Vitamin B12 (cobalamin) is a metal complex composed of a central cobalt ion bonded to six ligands. It is essential for major biological functions such as protein, fat and carbohydrate metabolism, the maintenance of the central nervous system, and the formation of red blood cells. Since mammals cannot synthesize cobalamin, dietary intake represents the only natural source for humans. Dairy products can provide significant levels of cobalamin; moreover, the European Food Safety Authority (EFSA) panel has set the recommended intake at 4 μg/day for adults. Vitamin B12 content was determined in milk and several matrices related to the process of transformation of the residual whey from Parmigiano Reggiano cheese-making to obtain ricotta cheese. In addition, vitamin B12 degradation during ricotta cheese shelf-life was studied. The analyses were performed using an ultra performance liquid chromatography-tandem mass spectrometry method. Results show that vitamin B12 amount in ricotta from dairy and experimental cheese-making brings respectively 1/8 to 1/4 of the adequate intake in adults established by EFSA. In addition, shelf-life experiment shows that cobalamine is fairly rapidly degraded in ricotta: light effect seems to be significant, even if the light exposure is short. The use of photoprotective packaging material increases B12 shelf-life in the early stage of storage.

High-Pressure Cold Pasteurization of Gilthead Seabream Fillets: Selection of Process Conditions and Validation of Shelf Life Extension

The objective of this study was to identify and kinetically study the most high-pressure (HP) resistant deteriorative factor of gilthead seabream (Sparus aurata) fillets aiming in their shelf life extension using in pack cold pasteurization technology. Fillets were HP processed (600 MPa, 25 °C, 5 min) and stored at 15 °C for 15 days, until spoilage. Lactobacilli were isolated from the spoiled fillets and were identified and classified as Pediococcus spp. The necessary HP process conditions for Pediococcus spp. cells inactivation were studied at various combinations of pressure (150–600 MPa) and temperature (20–40 °C) for appropriate time. The D values were calculated at all pressure–temperature combinations. The effect of temperature (z T) and pressure (z P) was estimated at all pressures and temperatures, respectively. According to the developed model for Pediococcus spp. inactivation, HP treatment of seabream fillets at 600 MPa and 25 °C for 5 min seemed to be capable for a 6-log10 reduction of the initial microbial load, potentially providing shelf life extension. Shelf-life experiments were conducted for validation. Untreated and HP treated at 600 MPa for 5-min samples were stored at 0, 5, 10 and 15 °C. Quality indices (colour, texture, microbial growth, sensory scoring) were monitored and kinetically modelled. Temperature dependence of quality loss rates was modelled by the Arrhenius equation. Microbial growth was well correlated with the sensory indices. HP treatment led to significant shelf life extension of fillets. Based on sensory scoring, the shelf life of the untreated samples was 11, 7, 4 and 3 days while for the HP-treated fillets 37, 27, 17 and 10 days after storage at 0, 5, 10 and 15 °C, respectively.

Turning waste into a resource: Study of the effect of containers made of giant reed weeds on the shelf life and quality of tomatoes and strawberries

T. Garcia-Ortuno, A.A. Carbonell-Barrachina, J. Andreu-Rodriguez, M.T. FerrandezGarcia, A. Calin-Sanchez, M. Ferrandez-Villena, and C.E. Ferrandez-Garcia. 2013. Turning waste into a resource: Study of the effect of containers made of giant reed weeds on the shelf life and quality of tomatoes and strawberries. Cien. Inv. Agr. 40(1): 149-159. Giant reed (Arundo donax L.) is currently one of the greatest invasive threats to Mediterranean-type river ecosystems worldwide and can be easily transformed into a cheap and sustainable material that can be used in the manufacturing of containers for the fruit and vegetable industry. Simple trays were prepared using giant reed, and their behavior was evaluated during storage of tomatoes and strawberries. The mechanical properties of the giant reed particleboards were assayed, and it was shown that they are suitable for industrial purposes. The quality of strawberries and tomatoes stored for 7 and 14 days, respectively, in plywood (control) and giant reed containers was comparable, with no significant differences found. The parameters analyzed included weight loss, titratable acidity, total soluble solids, the maturity index, and sensory quality parameters (color, presence of decay, freshness of odor, sourness, sweetness, freshness of flavor and firmness) using a trained panel. After the shelf-life experiments, the properties of containers made with giant reed were assayed, and all of the properties met the requirements established for stacking, compression, static bending and dynamic compression. For instance, all of the containers resisted more than 5000 kg of compressive strain, and the maximum deflection that the containers exhibited was 3.84 mm, which is smaller than the maximum of 6.1 mm allowed.

Postharvest quality of integrated and organically produced apple fruit

Apple cv. ‘Jonagold’ fruit were picked in three different regions of Belgium. In each region one organic and one integrated orchard with identical climatic and soil characteristics was sampled. Fruit were stored in air and under CA conditions (1% O 2, 2.5% CO 2) at 1 °C for 6 months. The acoustic stiffness, firmness, soluble solids contents, acid and sugar contents, and the aroma profile were measured. Quality parameters were analysed right after harvest and storage. At both times an additional shelf-life experiment was carried out to simulate the conditions in the commercial chain. The quality attributes of apples coming from different regions and different production systems did not differ significantly, neither at harvest nor after storage. There was a considerable softening during storage in air and shelf-life, but not under CA conditions. Immediately after harvest, high malic acid, quinic acid and sucrose contents were observed, while glucose and citric acid contents were higher after storage. The aroma profile changed during shelf-life, except for apples stored in air, which even immediately after storage already had an aroma profile comparable to that after shelf-life. The volatile responsible for the typical apple aroma (2-methylbutyl acetate) had the highest relative abundance after CA storage and subsequent shelf-life, followed by apples immediately after CA storage. The effect of storage conditions on the quality of the apples was in general much larger than that of the possible effects of the production system. Aroma profiles of air-stored and CA-apple converge during shelf-life conditions.

COMPARING THE PHYSIOLOGICAL CHANGES IN APPLES AND PEARS DURING SHELF-LIFE MEASURED BY FLUORESCENCE IMAGING

The physiological state of plants during their development can be determined using chlorophyll fluorescence, induced after excitation with UV-, blue-, green-, orange- or red-light. During fruit ripening and senescence, two major phenomena affect the level of chlorophyll fluorescence emission: (i) a loss of photosynthetic competence per unit chlorophyll leading to reduced PSII activity and (ii) a decrease in chlorophyll content. In this paper, chlorophyll fluorescence characteristics of some physiological changes in 'Conference' pears (Pyrus communis L.) and 'Jonagold' apples (Malus domestica Borkh.) during a shelf-life experiment are studied using the PEA (Plant Efficiency Analyser) and a custom build fluorescence imaging system (FIS). The apples and pears were bought in a local store and were followed during several days in order to detect physiological changes during this period. The results show that chlorophyll fluorescence imaging is more reliable compared to a point measuring technique such as the PEA and can be used to predict the shelf-life quality of 'Conference' pears and 'Jonagold' apples.

Changes in sensitivity for ethylene during storage of apple and banana fruits under hypobaric conditions

Apple fruits stored under hypobaric pressure (66 mbar) never produced autocatalytic ethylene or developed a respiratory climacteric during an 11-month storage period. Only a slight decrease in fruit firmness was measured during that time. When C 2H 4 was continuously supplied into the hypobarically operated storage containers, a considerable response was noticed at the beginning of the storage period. Later on, the effect of ethylene was marginal. Shelf-life experiments with these fruits after 2.5, 5, 7 and 10 months of storage at a reduced pressure revealed a similar decrease in sensitivity to C 2H 4 as far as respiration, softening and volatile flavor substances were concerned. The adverse effects on flavor and possible reasons for this are discussed in connection with similar observations of CA-stored fruits. Similar experiments with banana fruits did not show a diminished response to C 2H 4. Whether the higher storage temperature, the shorter storage period or physiological differences are responsible for this dissimilarity is presently not known.