End Of Shelf Life Research Articles

Development of predictive models evaluating the spoilage-delaying effect of a bioprotective culture on different yeast species in yogurt

Yeast spoilage of fermented dairy products causes challenges for the dairy industry, including economic losses due to wasted product. Food cultures with bioprotective effects are becoming more widely used to help ensure product quality throughout product shelf life. To assist the dairy industry when evaluating product quality throughout shelf life and the effect of bioprotective cultures, we aimed to build stochastic models that provide reliable predictions of yeast spoilage in yogurt with and without bioprotective culture. Growth characterizations of Debaryomyces hansenii, Yarrowia lipolytica, Saccharomyces cerevisiae, and Kluyveromyces marxianus at storage temperatures of 7, 12, and 16°C during a 30-d storage period were conducted in yogurt with and without a bioprotective culture containing Lacticaseibacillus rhamnosus strains. The kinetic growth parameters were calculated using the Buchanan growth model, and these parameters were used as baseline values in Monte Carlo models to translate the yeast growth into spoilage levels. The models were developed using 100,000 simulations and they predicted yeast spoilage levels in yogurt by the 4 yeast types. Each modeled yogurt batch was set to be contaminated with yeast at a concentration drawn from a normal distribution with a mean of 1 log10 cfu/mL and standard deviation of 1 log10 cfu/mL and stored for 30 d at a temperature drawn from a normal distribution with a mean of 6.1°C and a standard deviation of 2.8°C. Considering a spoilage level of 5 log10 cfu/mL, the predicted number of spoiled samples was reduced 3-fold during the first 10 d and by 2-fold at the end of shelf life when a bioprotective culture was added to the yogurt. The models were evaluated by sensitivity analyses, where the main effect factors were maximum yeast population, storage temperature, and yeast strain. The models were validated by comparing the model output to actual observed spoilage data from a European dairy using the bioprotective culture. When the model prediction, based on a mixture of the 4 specific yeast strains, was compared with spoilage data from the European dairy, the observed effect of bioprotective cultures was considerably higher than predicted, potentially influenced by the presence of contaminating strains more sensitive to a bioprotective culture than those characterized here. The developed Monte Carlo models can predict yeast spoilage levels in yogurt at specific production settings and how this may be affected by various parameters and addition of bioprotective cultures.

A comparison of the effect of X and gamma irradiation on red cell storage quality.

Irradiation of red cell components is indicated for recipients at risk of transfusion-associated graft vs. host disease. Current technologies available comprise of a gamma (γ) or an x source of radiation. The benefits of x vs. γ include non-radioactivity and hence no decay of the source. We aimed to compare the effect of the two technologies on red cell component storage quality post-irradiation. Paired units of red cell concentrates (RCC), neonatal red cell splits (RCS), red cells for intra-uterine transfusion (IUT) or neonatal exchange transfusion (ExTx) were either γ- or x-irradiated. Units were sampled and tested for five storage parameters until the end of shelf life. Equivalence analysis of storage quality parameters was performed for pairs of the same components (RCC, RCS, IUT or ExTx) that were either γ- or x-irradiated. Nearly all component comparisons studied showed equivalence between γ and x irradiation for haemolysis, ATP, 2,3-DPG, potassium release and lactate production. The exceptions found that were deemed non-equivalent were higher haemolysis with x irradiation for ExTx, lower 2,3-DPG with x irradiation for RCS irradiated early and higher ATP with x irradiation for IUT. However, these differences were considered not clinically significant. This study has demonstrated that a range of red cell components for use in different age groups are of acceptable quality following x irradiation, with only small differences deemed clinically insignificant in a few of the measured parameters.

Effects of Tea Polyphenol Treatments on the Quality and Microbiota of Crisp Grass Carp Fillets during Storage at 4 °C

We investigated the effects of tea polyphenol treatments on the quality and microbiota of crisp grass carp fillets during cold storage at 4 °C. Changes in the total viable count (TVC) and total volatile base nitrogen (TVB-N) of fillets were measured. The microbiota of the crisp grass carp was analyzed using high-throughput sequencing technique. The results indicated that tea polyphenol treatments inhibited bacterial growth and reduced TVB-N values of fish fillets, and subsequently extended their shelf life by 6 days. The high-throughput sequencing result showed that Pseudomonas was the most abundant bacteria in tea polyphenol-treated fish fillets at the end of shelf life, while Pseudomonas and Aeromonas were the most abundant bacteria in control samples. These findings suggested that tea polyphenol treatments could be used in future to extend the shelf life of crisp grass carp fillets and alter the bacterial communities responsible for spoiling fish.

Expiration Date of Ready-to-Eat Salads: Effects on Microbial Load and Biochemical Attributes.

When minimally processed vegetables reach their expiration date, expose an increased microbial load. This includes mainly spoilage microorganisms but also foodborne pathogens, thus affecting the quality and safety of highly consumed ready-to-eat salads. A total of 144 ready-to-eat salads from the Cypriot market were analyzed in an attempt to determine the effects of the expiration date on the microbial load and plant metabolic variables of the salads. Possible correlations between them were also investigated for the first time. Furthermore, the impacts of the season (winter, summer), salad producing companies and type of salad and/or their interactions with the tested parameters were investigated. Results revealed that the microbial load (mainly spoilage microorganisms, such as Pseudomonas spp., yeasts and molds) increased towards the end of the shelf life. The microbial load was differentiated among the five salad producers and/or the salad types, highlighting the importance of a common and safe sanitation-processing chain in the preparation of ready-to-eat salads. Summer was the season in which Escherichia coli counts were found to be higher for plain lettuce, while Staphylococcus spp. was increased numbers for the lettuce+endive/radicchio, lettuce+rocket and lettuce+chives type of salads. Additionally, an increased Staphylococcus spp. was observed for plain rocket salads in winter. All samples examined were found negative for Salmonella enterica and Listeria monocytogenes. Moreover, carbon dioxide production and damage indexes (hydrogen peroxide and lipid peroxidation) increased on expiration date on both winter and summer seasons, indicating plant tissue stress at the end of shelf life. These findings indicate that the expiration date and relevant shelf life of processed vegetables are important parameters to be considered when postharvest management is applied to these products, ensuring safety and quality.

Encapsulation of Sargassum boveanum Algae Extract in Nano-liposomes: Application in Functional Mayonnaise Production

In this study, brown algae extract (BAE) was encapsulated in nano-liposomes. Antibacterial activities of free and encapsulated (in nano-liposomes, BAE-NLs) BAE were evaluated by a micro-dilution method. The results indicated that encapsulation of BAE causes an enhancement of its antibacterial efficiency (about 50%) against P. aeruginosa, E. coli, and B. cereus. Different formulations of mayonnaise were prepared including positive controls (sample containing 200 mg/kg butylated hydroxytoluene (BHT-200), or 1000 mg/kg sodium benzoate (SB-1000)) and samples containing 1000 mg/kg of free and encapsulated BAE. Also, pH, color attributes, lipid oxidation, microbial growth, and sensory characteristics of the samples were monitored during four months of storage at ambient temperature. At the end of storage, BAE-NLs and BHT-200 mayonnaises had significantly lower peroxide value and thiobarbituric acid reactive substances than the control and free BAE (p < 0.05). The color attributes, including lightness, redness, and yellowness of mayonnaise, were undesirably changed by the addition of free BAE. Total viable and fungal counts of the samples incorporated with BAE-NLs and SB-1000 presented a pronounced decrease in comparison with control and samples containing free BAE at the end of shelf-life. Free BAE had an unpleasant effect on color, taste, and overall acceptability of mayonnaise, but the assessor acceptability of samples was remarkably improved after fortification with BAE-NLs. To conclude, nano-encapsulation is an appreciable approach to enhance the bioactivities of BAE.

Effect of peroxyacetic acid treatment and bruising on the bacterial community and shelf-life of baby spinach

The importance of leaf integrity, i.e. the effects of bruising (mechanical damage), and sanitisation with peroxyacetic acid (PAA) on bacterial communities of ready-to-eat baby spinach remains unclear. Two shelf-life studies were conducted at 4 °C to investigate the effect of bruising and sanitisation on the growth of spoilage microorganisms. In the first experiment, both bruising treatments (100% and 40% of leaves) halved shelf life to 12 d, whereas intact leaves had a shelf-life of 23 d. Bruising had no influence on bacterial diversity during shelf-life, though some differences in the relative abundance of minor genera were observed. Pseudomonas and Pantoea were the most dominant bacterial genera, regardless of bruising treatment. High throughput amplicon sequencing also identified other spoilage bacteria including Chryseobacterium, Stenotrophomonas, Bacillus, Sphingobacterium, Erwinia and Flavobacterium. In the second experiment, washing of intact baby spinach with a sanitiser (80 mg/L: PAA) reduced microbial load as determined by aerobic plate count but did not immediately affect the presence/relative abundance of most of the genera of spoilage bacteria observed. During shelf-life, the bacterial diversity of sanitised leaves was significantly lower than on water-washed leaves. Although sanitisation resulted in a higher initial log reduction in microbial load compared to control (portable tap water), sanitisation did not extend the shelf life of baby spinach (23 d). Sanitised spinach had reduced bacterial diversity however, by the end of shelf life, both sanitised and water-washed spinach was dominated by Pseudomonas and Pantoea spoilage bacteria. This study demonstrated for the first time that the shorter shelf life of bruised leaves was related to faster microbial growth rather than changes in bacterial diversity or community composition.

Behavior of the Biological Control Agent Bacillus thuringiensis subsp. aizawai ABTS-1857 and Salmonella enterica on Spinach Plants and Cut Leaves.

Fresh produce has been identified as an important vehicle for the transmission of foodborne pathogens. This study evaluated the behavior of vegetative cells and spores of Bacillus thuringiensis, one of the main biological control agents (BCAs) used in the world, and Salmonella enterica on spinach plants (pre-harvest) and spinach cut leaves (post-harvest) at 12°C, experimentally inoculated as single or co-cultures. The results evidenced that spray-inoculated commercial BCA containing Bacillus thuringiensis subsp. aizawai ABTS-1857 (BTa ABTS-1857) spores persisted well on spinach leaves in both pre- and post-harvest simulations. However, when BTa ABTS-1857 vegetative cells were spray-inoculated, more than 2 log reductions in the counts of B. thuringiensis were observed during 20 days pre- and 5 days post-harvest simulations, respectively. The counts of S. Montevideo on the spinach cut leaves during post-harvest storage at 12°C for 5 days remained unchanged, whereas 1 log reduction was noted during pre-harvest. Moreover, during pre-harvest simulation, when co-inoculated with BTa ABTS-1857 vegetative cells or spores, additional 0.5 or 1.0 log reductions were detected on the counts of S. Montevideo in the spinach leaves on the 10th day. These results were obtained under laboratory conditions, and further findings in longitudinal studies from farm (in the agricultural field) to retail (end of shelf life) will contribute to understanding of the role of B. thuringiensis as a BCA on growth/survival of Salmonella spp. in fresh produce.

Sensory properties of iodine-biofortified potatoes

The present study assessed the sensory impact of potatoes biofortification with iodine and the stability of iodine during six months of storage. Four biofortified cultivars (Cupido, Marabel, Orchestra and Universa) and their controls (non-biofortified) were evaluated. The present study assessed the sensory impact of potatoes biofortification with iodine and the stability of iodine during six months of storage. Four biofortified cultivars (Cupido, Marabel, Orchestra and Universa) and their controls (non-biofortified) were evaluated. Descriptive analysis was applied with a panel to describe the sensory properties, and triangle tests were applied with consumers to evaluate perceivable differences between controls and respective biofortified samples at the end of shelf life. Iodine content was quantified on raw potatoes for three periods of storage. Descriptive analysis showed some differences between controls and iodine-biofortified samples, especially in texture (hardness). However, consumers did not significantly discriminate fortified from unfortified samples. Iodine was stable during storage in all varieties. Orchestra cultivar showed the highest iodine content, while Universa the lowest.

Commercial wash of leafy vegetables do not significantly decrease bacterial load but leads to shifts in bacterial species composition

Production of leafy vegetables for the “Ready-to-eat”-market has vastly increased the last 20 years, and consumption of these minimally processed vegetables has led to outbreaks of food-borne diseases. Contamination of leafy vegetables can occur throughout the production chain, and therefore washing of the produce has become a standard in commercial processing. This study explores the bacterial communities of spinach (Spinacia oleracea) and rocket (Diplotaxis tenuifolia) in a commercial setting in order to identify potential contamination events, and to investigate effects on bacterial load by commercial processing. Samples were taken in field, after washing of the produce and at the end of shelf-life. This study found that the bacterial community composition and diversity changed significantly from the first harvest to the end of shelf-life, where the core microbiome from the first to the last sampling constituted <2% of all OTUs. While washing of the produce had no reducing effect on bacterial load compared to unwashed, washing led to a change in species composition. As the leaves entered the cold chain after harvest, a rise was seen in the relative abundance of spoilage bacteria. E. coli was detected after the washing indicating issues of cross-contamination in the wash water.

Pork Liver Freshness Evaluated through Spoilage Microbiota and a Consumer Test in Shelf Life Extension Experiment

Pork liver is an affordable product, very much appreciated by some consumers. Packaged pork liver has a short shelf life that can represent an additional cost to the producers. This work aimed to assess the relationship between consumer acceptability, evaluated through both a test made live with photography and samples to be smelled and an internet survey platform based only on photography, and the counts of the main spoilage microorganisms, on pork liver samples stored from the actual end of shelf life (ESL) and two extra days of storage times, ESL + 2 and ESL + 4. The results indicate limited usefulness of microbial counts, once they were generally very similar between accepted and nonaccepted samples, with total viable count below 7 Log CFU/g. Both methodological approaches revealed that there is no margin to extend the shelf life from the three days previously established by the manufacturer. It was observed that pork liver packaged with modified atmosphere had similar evaluations of freshness using internet-based or live test with consumers, with a drop in purchase intention from 87.5% at ESL to 13.2% at ESL + 2, when the assessment was made through the internet-based test. When the test was made live, the purchase intention had the same trend, but the drop was smaller, from 61.5 at ESL to 21.2% at ESL + 2. The purchasing intention was lower when the consumers had the opportunity to smell the samples but considering the decision of defining the end of shelf life based on 50% of consumers accepting, it was similar in almost all the cases.

The efficiency of stabilizing the oxidative spoilage of meat-containing products with a balanced fat-acid composition

This paper reports a study of the fatty acid composition of a meat-containing semi-smoked sausage with Peking duck meat that established the biological effectiveness of the product's fat. The rosemary extract application efficiency has been investigated for the course of oxidation processes in a semi-smoked sausage with a high content of unsaturated fatty acids. The high content of the monounsaturated FA C18:1 ω-9 (oleic) has been determined experimentally, 40.37 g/100 g fat. The content of the PUFA ω-3 in a meat-containing semi-smoked sausage made from the meat of Peking duck is 1.22 g/100 g of fat, which satisfies the daily recommended need in essential FA by 27 %. The ratio between the families of the FA w-3/w-6 in the developed products is at least 1:11 at the recommended physiological norms of the perfect fat composition in a meat product of 1:10. The current study has confirmed the high antioxidant activity of rosemary extract and the effective inhibition of the process of lipid oxidation in meat-containing sausages. Introducing a rosemary extract in the amount of 0.02–0.06 % slows down the hydrolytic oxidation of minced meat lipids by 29.13–35.00 %, inhibits the peroxidation of lipids in the meat-containing semi-smoked sausage, thereby reducing the number of peroxides by almost five times. It has been confirmed that stabilizing the peroxidation of lipids in the meat-containing semi-smoked sausage made from Peking duck meat with a high concentration of unsaturated fatty acids should, as a consequence, reduce the concentration of secondary oxidation products. The number of aldehydes and ketones was least at the end of shelf-life of the finished products and was 0.38–0.80 mg MA/kg of the product, which is 2.54–3.94 times lower than that of control sample. The greatest stabilizing effect has been achieved when introducing a rosemary extract in the amount of 0.06 %, which makes it possible to reduce the indicators of oxidative spoilage of fat by more than twice.

Buffalo milk increases viability and resistance of probiotic bacteria in dairy beverages under in vitro simulated gastrointestinal conditions

Probiotic dairy beverages prepared from buffalo and cow milks with different levels of whey (0, 25, and 50%) were evaluated for kinetic fermentation parameters, protein and fat contents, post-acidification profile, viability of Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillus acidophilus during 21 d of refrigerated storage, and resistance to in vitro gastrointestinal conditions. Progressive acidification that occurred during storage of all dairy products was reduced in the presence of whey. Lactic acid bacteria showed viable cell counts at the end of shelf life, with the highest values (7.33 to 8.83 log cfu/mL) detected in buffalo dairy products. Compared with fermented cow milk products, those made with buffalo milk showed better bacterial viability during in vitro simulated gastrointestinal digestion, which suggests a beneficial protective effect on human microbiome.

Effect of some Pre-Harvest Treatments on Quality of ʺCrimson Seedlessʺ Grapes During Cold Storage and Shelf Life

This work was carried out during two successive seasons (2017 and 2018) to examine the response of ʺCrimson Seedlessʺ grapes to some pre-harvest treatments i.e. jasmonic acid (JA) at (4 and 8) mM/L and grapefruit seed extract (GSE) at (0.5 and 1) mM/L on some berries quality parameters under cold storage and shelf-life conditions. Vines were sprayed in two application times at (25th and 30th August) during 2017 and 2018, respectively. The non-ionic surfactant Tween-20 at 0.05% (v/v) was added to all treatments to reduce the surface tension and increase the contact angle of sprayed droplets. Results showed that both jasmonic acid and grapefruit seed extract treatments at different concentrations were significantly effective in reducing weight loss, berry decay, berry shatter, and total loss in cluster weight percentages during the cold storage period and shelf life as compared to the control. Also, the previous treatments significantly increased berry firmness, soluble solid content (SSC%), SSC/acid ratio, and total anthocyanin contents, where it was caused a significant decrease in total acidity percentage during the cold storage period and shelf life in comparison with control. Furthermore, the lowest values of weight loss, berry shatter, berry decay and total loss in cluster weight were founded by JA at 8 mM and GSE at 1 mM at the end of shelf life in comparison with other treatments. It could be concluded that JA at 8 mM and GSE at 1 mM as preharvest treatments are applicable for improving the storability of ʺCrimson Seedlessʺ grapes and maintaining their quality during cold storage and shelf life.

UMUR SIMPAN DAN KUALITAS MIKROBIOLOGIS TELUR ITIK ASIN RENDAH SODIUM DENGAN PENGGUNAAN EKSTRAK DAUN JATI DAN PENGOVENAN

Salted duck egg is a duck egg preservation product which nutritionally rich in unsaturated fatty acid, fat, protein, and minerals, as well as has lower phospholipids and cholesterol levels than the fresh eggs. The salting (sodium chloride, NaCl) treatment during salted egg processing produces desirable egg yolk texture, salty taste, and longer the shelf life. The previous study reported that hypertension prevalence and stroke risk have a negative correlation to potassium intake but positively correlated to the sodium intake. The authors have reported the development of low-sodium salted eggs having antioxidant potential through salting process innovation by potassium chloride (KCl) substitution and teak leaf extract addition. The potential of intensive duck eggs for low-sodium salted egg production also has been reported in the previous author's study. This research aims to evaluate the shelf life and microbiological quality of low-sodium salted eggs prepared with salting process innovation and oven treatment using intensive duck eggs. Oven treatment carried out at the temperature of 100 0 C with various oven duration. The oven duration that produces low sodium salted eggs with the highest sensory quality was chosen for salted egg preparation. The shelf life of low-sodium salted eggs was determined by measuring the sensory quality degradation during storage at ambient temperature. Microbiological quality conducted by analyze the total plate count (TPC) of low sodium salted eggs at initial and the end of shelf life. The research result showed that 30 minutes oven duration produces the highest sensory quality. The shelf life of the low sodium salted eggs prepared with 30 minutes oven duration was 12 days. The TPC of fresh prepared low sodium salted egg reach to 6.4 x10 3 CFU/g and increased to 2,4x10 6 CFU/g at the end of the shelf life. These results provide an alternative to the development of intensive duck eggs for the production of low-sodium salted eggs as innovation product of duck salted eggs which were safer and has better quality for the Indonesian community

Active exopolysaccharides based edible coatings enriched with red seaweed (Gracilaria gracilis) extract to improve shrimp preservation during refrigerated storage

Active edible coatings from microalgal exopolysaccharides (EPS) enriched with different concentrations of red seaweed extract (RSE) (0.5, 1 and 1.5% (w/v)) were developed and their effects on shrimp quality with refrigerated storage (4 ± 1 °C) were studied over a period of 8 days. Untreated and treated shrimp were regularly evaluated bacteriologically (total viable bacteria, psychrotrophic bacteria and Enterobacteriaceae counts), chemically (pH, TVB-N, TMA-N, PV, TBARS), texturally and sensorially. The coating of a mixture of EPS and RSE, significantly reduced (p < 0.05) TVB-N, TMA and TBARS values. With storage, EPS coatings containing RSE at 1 and 1.5% were most effective in the inhibition of the enumerated bacterial species, especially psychrotrophic bacteria. Also, EPS + RSE coated samples had lower polyphenol oxidase activity and better oxidative stability (p < 0.05) until the end of shelf life. Generally, EPS coatings significantly improved hardness and color of shrimp. Moreover, sensory evaluation showed that the initial sensory attributes of shrimp were not significantly affected with any treatment. Overall, the results showed that the application of EPS-based coating treatments led to a quality improvement and extended shelf life of refrigerated shrimp.

Assessment of growth and survival of Listeria monocytogenes in raw milk butter by durability tests

Butter is a complex matrix characterized by a high fat content. Existing publications on the behavior of Listeria monocytogenes in this type of food reported contrasted results. This study was performed to provide further information and data about raw milk butter's ability to support survival or growth of L. monocytogenes. Durability tests were performed on naturally contaminated samples of raw milk butter with various physico-chemical characteristics. At the end of shelf life, no growth of L. monocytogenes was observed in the studied butters, regardless of their physico-chemical characteristics (pH, aw, water dispersion index and salt concentration) and the initial level of contamination. The number of positive samples and the colony counts of L. monocytogenes were even decreased at the end of the storage period.

A Comparison of Water Chilling and Air Chilling on Poultry Shelf Life

ObjectivesIn the U.S. water immersion chilling (WC) is commonly used to chill poultry, while the E.U. utilizes air chilling (AC). With demand for poultry continuing to rise, poultry products with longer shelf life and less food waste will be needed. Meanwhile, widespread efforts to reduce natural resource and energy expenditures, such as water, as a means of enhancing sustainability, exist across the meat industry, including the poultry industry. Therefore, the objective of this study was to compare the impact of WC and AC on the shelf life and meat quality of bone-in and boneless chicken breast.Materials and MethodsA total of 256 eviscerated non-chilled chicken carcasses were obtained from a commercial processing facility in California and transported to the UC Davis meat laboratory within 2 h. Carcasses were randomly and evenly assigned to either water immersion chilling (WC) or air chilling (AC) and then were evenly assigned to be fabricated into bone-in (BI) or boneless (BL) breast. The breast samples were subsequently packaged onto polystyrene trays, overwrapped, and placed into cardboard boxes for dark storage at 4°C for either 7d (phase 1) or 14d (phase 2). Then breast samples were placed into a retail display case maintained at 4°C for 3d. Instrumental color measurement was performed every 12 h during retail display. Microbial analysis was conducted for samples collected on arrival, post chilling, post-fabrication, after dark storage at 4°C for 7d or 14d and after 3d retail display (n = 10 per sampling point per treatment). A panel of 8 untrained participants were asked to evaluate the color and their willingness to purchase (for example color: desirable, acceptable, unacceptable). Analysis of variance was conducted to evaluate the effect of chilling method and storage time on all dependent variables using Proc Mixed in SAS (version 9.4).ResultsThe WC chicken possessed lower psychrotrophic bacterial counts (1.05 log CFU/g) pre-fabrication than the AC chicken (2.12 log CFU/g), indicating that WC may remove a portion of the psychrotrophic bacteria. However, no difference in mesophilic bacterial counts was observed between the two treatments for pre-fabrication samples. The WC chicken and AC chicken, regardless of fabrication type, reached the end of shelf life (7 log CFU/g) at the 14d. The BL samples, regardless of chilling method, had lower total microbial counts throughout storage and display than the BI samples, since the removal of the skin physically removed the general microbial population as well. In terms of objective color, the a* and b* values were higher for AC breast, suggesting that AC breast was more red and yellow than WC breast through the display time. Chilling method did not have an impact on subjective color measurement. During phase 1, untrained panelist considered the color of BL chicken breasts more desirable than the BI breasts. During phase 2, regardless of chilling method or fabrication type, the desirability of color by untrained panelist decreased as display time increased.ConclusionThe results indicate that chilling method had a minimal impact on the shelf life in terms of the microbial counts. Although AC chicken breast tend to be more yellow based on objective color measurement, consumers did not detect a distinct color difference of chicken treated with air chilling or water chilling.

STABILITAS ANTOSIANIN DAN AKTIVITAS ANTIOKSIDAN TEPUNG BERAS HITAM BERDASARKAN JENIS KEMASAN DAN LAMA PENYIMPANAN

Black rice flour during storage has the disadvantage of reducing the antioxidant content and antioxidants present in black rice flour due to improper packaging for storage so that the pH increases, the color will disappear so that the anthocyanin content will also decrease during storage. This study aims to determine the influence of packaging type and storage time to levels of anthocyanins, antioxidant activity, moisture content, and color of black rice flour. This research uses a factorial completely randomized design consisting of 2 factors: first factor type of packaging (PP and Alufo) with each thickness of 0.5 mm and second factor storage duration (0 days, 14 days, 28 days, 42 days, and 56 days) in room temperature. The results of statistical test showed that the type of packaging and storage duration influenced the anthocyanin content, antioxidant activity, moisture content, and color. Antosianin content of black rice flour at the end of shelf life on PP packaging of 5.39 ppm sample and Alufo 14.14 ppm sample. Antioxidant activity at end of shelf life in packing of PP equal to 18,6% and Alufo 24,48%. Water content at end of shelf life on packing PP 2,34% and Alufo 2,65%. The color is at the end of shelf life on the packaging of PP 8,351 and Alufo 7,568.

NILAI TBA, FFA, KADAR AIR DAN SIFAT SENSORI KERIPIK KENTANG BERDASARKAN JENIS KEMASAN DAN LAMA PENYIMPANAN

Potato (Solanum tuberosum L.) is one type of tubers are widely consumed by the community because it tastes good and contains high carbohydrates. Potato damage easily occurs because the water content in potatoes is high enough that is 80 percent. Based on that, it is necessary to do the processing to extend the life of the potato store. This study aims to determine the effect of packaging type and storage time to the value of TBA, FFA, Water Content and Sensory Character of Potato Chips. This study used a factorial completely randomized design consisting of 2 factors: packaging type (PP, PE, and aluminum foil) with each thickness of 0.5 mm and storage time (0 days, 7 days, 14 days, 21 days and 28 day) in room temperature. The result of statistical test showed that the type of packaging and storage time had an effect on FFA value, water content and sensory character of potato chips while the value of TBA had no significant effect. Level of potato chip TBA at end of shelf in packing PP 2,412 mg malonaldehid / kg sample, PE 3,365 mg malonaldehid / kg and aluminum foil 2,787 mg malonaldehid / kg sample. FFA value at end of shelf life on packing PP1,173% ALB sample, PE 1,548% ALB sample, and Alumunium foil 1.173% ALB sample. Water content at end of shelf life on PP 7.040%, PE 3,933%, and Alumunium foil 3,003%. The result of statistical test shows that there is influence of packaging type and storage time to FFA value, water content and sensory character of potato chips.

Shelf life prediction model of postharvest table grape using optimized radial basis function (RBF) neural network

Purpose The purpose of this paper is to develop a common remaining shelf life prediction model that is generally applicable for postharvest table grape using an optimized radial basis function (RBF) neural network to achieve more accurate prediction than the current shelf life (SL) prediction methods. Design/methodology/approach First, the final indicators (storage temperature, relative humidity, sensory average score, peel hardness, soluble solids content, weight loss rate, rotting rate, fragmentation rate and color difference) affecting SL were determined by the correlation and significance analysis. Then using the analytic hierarchy process (AHP) to calculate the weight of each indicator and determine the end of SL under different storage conditions. Subsequently, the structure of the RBF network redesigned was 9-11-1. Ultimately, the membership degree of Fuzzy clustering (fuzzy c-means) was adopted to optimize the center and width of the RBF network by using the training data. Findings The results show that this method has the highest prediction accuracy compared to the current the kinetic–Arrhenius model, back propagation (BP) network and RBF network. The maximum absolute error is 1.877, the maximum relative error (RE) is 0.184, and the adjusted R2 is 0.911. The prediction accuracy of the kinetic–Arrhenius model is the worst. The RBF network has a better prediction accuracy than the BP network. For robustness, the adjusted R2 are 0.853 and 0.886 of Italian grape and Red Globe grape, respectively, and the fitting degree are the highest among all methods, which proves that the optimized method is applicable for accurate SL prediction of different table grape varieties. Originality/value This study not only provides a new way for the prediction of SL of different grape varieties, but also provides a reference for the quality and safety management of table grape during storage. Maybe it has a further research significance for the application of RBF neural network in the SL prediction of other fresh foods.