Packaging to prolong shelf life of preservative-free white bread

خواص مکانیکی خمیر نقش مهمی در صنایع پخت ایفا می‌کنند و در مواردی از قبیل تثبیت افزودنی‌ها و مطالعه تاثیر آنها بر سایر خواص خمیر و نان می‌توانند مورد توجه واقع شوند. در این پژوهش، از روش‌های چندمتغیره متقارن (تعیین ضرایب همبستگی و آنالیز مولفه‌های اصلی) و نامتقارن (سطح پاسخ و رگرسیون حداقل مربعات جزئی) به‌منظور مطالعه تاثیر اجزاء ژل بهبوددهنده بر خواص مکانیکی خمیر نان بربری، ارتباط خواص مکانیکی خمیر با سایر خواص خمیر و نان و نیز بهینه‌سازی فرمول ژل استفاده گردید. نمونه‌های ژل بهبوددهنده، محتوی 0 تا g100/g 5/0 سدیم استئاروئیل لاکتیلات، داتم و پروپیلن گلیکول بودند. نتایج نشان داد که با توجه به تغییر مقدار و نوع اجزاء فرمولاسیون ژل، دامنه وسیعی از تغییرات در خواص مکانیکی خمیر ایجاد می‌شود و از اختلاط g100/g 5/0 سدیم استئاروئیل لاکتیلات، g100/g 5/0 داتم و g100/g 5/0 پروپیلن گلیکول بهترین حالت حاصل می‌گردد. ضرایب همبستگی بین خواص مکانیکی خمیر با خصوصیات فارینوگرافی خمیر، کیفیت، جنبه‌های حسی، پردازش تصویر و ماندگاری نان بررسی گردید. همچنین آنالیز مولفه‌های اصلی ثابت نمود که قادر به استخراج اطلاعات مناسبی است و می‌تواند به‌عنوان یک روش آسان برای تحلیل و تفسیر خواص مکانیکی خمیر و ارتباط آنها با سایر خواص خمیر و نان مورد استفاده قرار گیرد. مدل‌های رگرسیونی حداقل مربعات جزئی نیز برای تعیین ارتباط بین خصوصیات مکانیکی خمیر با خصوصیات فارینوگرافی خمیر، خصوصیات کیفی، حسی، پردازش تصویر و ماندگاری نان به‌کار برده شد. نتایج حاصل از آنالیزهای آماری نشان داد که خصوصیات مکانیکی خمیر، قادر به پیشگویی حداقل 50% از خصوصیات خمیر و نان هستند.

PurposeWheat is the staple food in many parts of the world and bread is one of the most important products of wheat flour. There is a need for innovations in bread making to increase its shelf life and consumer's attraction. Fermentation is mostly done by yeast but it does not produce appreciable amounts of organic acids, which are required to enhance the shelf life of bread. The present study aims to determine the effect of bacterial and yeast culture blends on the quality and shelf life of sourdough bread and to observe the sugar utilization during fermentation.Design/methodology/approachThree treatments were made using different blends of bacterial cultures (homo‐fermentative and hetero‐fermentative) and baker's yeast compared with a control having only baker's yeast. Chemical analysis, sugar utilization (Sucrose, glucose and fructose) through high performance liquid chromatography, sensory characteristics (both internal and external) and microbial count (Bacterial and fungal count) for each treatment were conducted at different storage intervals.FindingsThe hetero‐fermentative bacteria i.e. Lactobacillus plantarum along with baker's yeast exhibited the best results regarding the utilization of sugars during fermentation (after 3 h of fermentation 0.0158 mg/ml sugar remained), objective evaluation of bread and its sensory characteristics. The bread prepared using the blend of hetero‐fermentative bacteria (0.5 per cent) and yeast (0.5 per cent) also showed greater resistance against bacteria (9×101 cfu/g after 60 h of storage) and mold (1.1 × 102 cfu/g after 60 h of storage) growth.Research limitations/implicationsHetero‐fermentative bacteria along with baker's yeast can be utilized in sour dough to improve major bread characteristics. This study is a step further in improving the shelf life of sourdough.Originality/valuePresently only baker's yeast is being used by bread industry for fermentation purpose but a blend of bacterial culture along with baker's yeast can give better performance for better quality and shelf life of the bread.

This study aimed to determine the effects of carbon dioxide concentration in modified atmosphere packaging (MAP) on the quality criteria and shelf life of whole wheat flour bread. Four different concentrations of CO2 and N2 gases (30% CO2 + 70% N2, 50% CO2 + 50% N2, 70% CO2:30% N2 and 100% CO2) were applied to the bread samples, which were packaged with PA/EVOH/LDPE (polyamide/ethylene vinyl alcohol/low‐density polyethylene). The samples were stored at room temperature (25°C ± 1°C) for 13 days. The control group was packaged using BOPP (bi‐oriented polypropylene) under atmospheric air as in traditional current use. The effects of MAP on headspace gas analysis, pH, moisture content, water activity, water‐holding capacity, blue value, hardness, total mould and yeast count and sensory evaluation were analysed on days 0, 3, 4, 5, 7, 10 and 13. The results showed that the most effective gas combination in extending the shelf life of whole wheat bread was 100% CO2, and its shelf life was 10 days, whereas it was only 3 days for the control group. Increasing concentrations of CO2 significantly affected mould and yeast growth. As the CO2 concentration increased, the bread exhibited higher water‐holding capacity and blue values, which are important indicators for bread staling. An improved preservation of sensory properties was observed in proportion to increasing CO2 concentrations. However, the CO2 gas concentration did not affect the hardness of the bread. Overall, the study suggests that MAP technology, particularly using 100% CO2, can effectively extend the shelf life of whole wheat flour bread without the need for preservatives, not only extending the microbiological shelf life but also increasing the sensory shelf life. The species that grew in air‐packaged samples were suppressed under modified atmosphere conditions and chalk mould fungi were the dominant and shelf life‐impacting species in the MAP samples. These findings could be beneficial in reducing bread wastage, which is a critical issue in today's society due to the limited shelf life of bread caused by rapid microbiological deterioration or staling.

Ready-to-eat macaroni and cheese filled in novel oxygen scavenger and metal oxide–coated high-barrier polymer packages were processed in pilot scale 915-MHz microwave-assisted thermal sterilization system (MATS). Also, aluminum foil packages were processed in Allpax retort system to compare packaging performance. Physicochemical and sensory attributes of macaroni and cheese packaged in different oxygen and water vapor transmission rates were evaluated and stored for 6 months at 37.8 °C. Findings showed oxygen transmission rate (OTR) increase by 2–7 times and water vapor transmission rate (WVTR) increase by 2.5–24 times after MATS processing. OTR of polymeric packaging had no significant effect on vitamin A and vitamin E, shear force, and food color. Comparable results between polymeric and aluminum foil packaging were observed throughout the shelf life. This indicates that oxygen scavenger and high-barrier packaging with OTRs ~ 0.03–0.34 cc/m2 day and WVTRs ~ 0.62–7.19 g/m2 day can be used for ready-to-eat meals with extended shelf life for soldiers and astronauts.

Pane Toscano DOP, a traditional sourdough bread from Italy, has a limited shelf life, typically lasting only a few days. Extending its shelf life without the use of synthetic preservatives is essential to meet the rising demand for clean-label products and to reduce food waste. This study aimed to identify the most effective packaging strategy to extend the shelf life of Pane Toscano DOP. Two packaging systems were evaluated: single-package and bag-in-bag systems. In the single-package setup, bread was packaged in PET/PE under different headspace conditions: ambient air (C1), air + Everfresh® Spray (EVF, a natural aromatic extract) (C2), CO2 only (C3), and CO2 + EVF (C4). In the bag-in-bag system, bread was first placed in a PLA primary package containing air and then enclosed within a PET/PE secondary package filled with either air (T1), air + EVF (T2), CO2 only (T3), or CO2 + EVF (T4). Shelf life of bread under different packaging conditions was evaluated based on the appearance of visible mold growth. T4 exhibited the longest shelf life, maintaining acceptable quality for 41 days, followed by T3 with 34 days. Air packaged samples C1 and T1 had the shortest shelf life of only 6 days, while C2, T2, and C3 each maintained quality for 20 days. These findings demonstrate that the use of modified atmosphere packaging, bag-in-bag systems, and aromatic headspace extracts can significantly extend the shelf life of artisanal breads, such as Pane Toscano DOP. This approach offers viable alternatives to synthetic preservatives while maintaining traditional product formulations.

Quality of pasteurized products can be affected by the combination of temperature abuse and gas barrier properties, especially oxygen transmission rate (OTR), of packaging films. Carrot puree was thermally pasteurized (90 °C, 14 min) and stored in three different types of pouches (OTR—0.99 ± 0.05 [F‐1], 29.8 ± 1.38 [F‐30], and 80.9 ± 2.15 [F‐81] cm3 m−2 day−1) at different temperatures (4, 8, and 13 °C). Weight loss, pH, instrumental color, β‐carotene, and ascorbic acid were evaluated over a 100‐day storage period. Results show that film OTR and temperature had a significant (p < 0.05) effect on food quality and nutritional attributes. High‐barrier film (F‐1) retained quality, while low‐barrier film (F‐81) increased losses during processing and storage for all parameters tested. High‐barrier film demonstrated stable color values (a* and b*) and significantly (p < 0.05) higher retention of β‐carotene during storage period. Ascorbic acid retention varied from 0 to 89%, depending upon packaging type. Based on ascorbic acid degradation kinetics, activation energy and Q10 values ranged from 20.3–72.3 kJ/mol and 1.36–2.96, respectively.Practical applicationsPasteurized food products have limited shelf life under refrigerated conditions. The shelf life of these products can be reduced by the combined effect of temperature abuse and gas barrier properties of packaging films. There is scarce information in the literature focusing on the shelf life studies of in‐pack thermally pasteurized products as a function of gas barrier properties. The selection criteria of films for pasteurized products are complex. Generally, higher the barrier properties needed higher is the cost of packaging. This study demonstrated the suitability of medium‐barrier films for in‐pack pasteurization; and combined effect of temperature abuse and gas barrier properties on the nutrient retention.

Korean melon (K-melon, Cucumis melo L. var. makuwa) is a key horticultural crop in the Republic of Korea, but its short shelf life restricts long-distance export. This study evaluated the modified atmosphere (MA) films of varying oxygen transmission rates (OTR) at controlled atmosphere (CA) storage under real maritime export conditions to Vietnam. In the non-permeable OTR 0 (Control) treatment, internal O2 rapidly declined below the anaerobic compensation point (1.67% at 10d and 0.47% at 10+3d) while CO2 accumulated to 32–36%. This ultra-low oxygen environment induced anaerobic metabolism, evidenced by strong accumulation of fermentative metabolites such as lactic acid, acetoin, and 2,3-butanediol, along with glucose/fructose retention and increases in alanine and γ-Aminobutanoic acid (GABA). These changes disrupted glycolysis and the Tricarboxylic acid cycle (TCA), consistent with CA shock, and were accompanied by rind blackening, elevated weight loss, and hue angle shifts toward yellow-orange. By contrast, OTR 10,000 and OTR 30,000 films significantly suppressed weight loss and color changes. Partial least squares-discriminant analysis (PLS-DA) identified volatile organic compounds, namely acetoin, 2,3-butanediol, and hexanal, as key discriminant metabolites, with OTR 30,000 clearly separated from other treatments at 10+3d, indicating minimal fermentation and oxidative stress. Microbial assays revealed a dose-dependent reduction in bacterial counts with increasing OTR, while fungal growth was most strongly suppressed under OTR 10,000. Overall, OTR 30,000 maintained the lowest and most stable levels of stress-related metabolites, minimized microbial proliferation, and preserved metabolic stability throughout shipping. This study provides the first quantitative evidence of anaerobic metabolic transition and primary metabolite accumulation in K-melons under actual export trials. The findings demonstrate that optimizing MA film permeability, particularly OTR 30,000 films, offers a practical and cost-efficient strategy to extend shelf life, maintain quality stability, and enhance the global export potential of K-melons.

Fully renewable oxygen barrier thermoplastic starch (TPS)/sugar alcohol blown films were innovatively prepared by blending proper loadings of Erythritol (ET), Sorbitol (ST), and Lactitol (LT) and supercritical carbon dioxide (scCO 2 ) assistance. The oxygen transmission rate (OTR) values of the properly prepared scCO 2 TPS x ET y , scCO 2 TPS x ST y, and scCO 2 TPS x LT y films reduced to 4.3, 6.6, and 12.5 cm 3 /m 2 ∙day∙atm, which are about 5–28 times smaller than those of the conventional TPS films reported in the literature. The free‐volume‐cavity characteristics (FVCC) and OTR detected for TPS x ET y (or scCO 2 TPS x ET y ), TPS x ST y (or scCO 2 TPS x ST y ), and TPS x LT y (or scCO 2 TPS x LT y ) films diminished to a minimum, as their ET, ST and LT loadings came near an optimal value. Slightly smaller OTR and FVCC values were detected for scCO 2 TPS x ET y , scCO 2 TPS x ST y, and scCO 2 TPS x LT y films than those of corresponding TPS x ET y , TPS x ST y , and TPS x LT y films prepared without scCO 2 ‐assistance. The smallest OTR and FVCC detected for the properly prepared TPS x ET y (or scCO 2 TPS x ET y ), TPS x ST y (or scCO 2 TPS x ST y ), and TPS x LT y (or scCO 2 TPS x LT y ) films diminished with decreasing sugar alcohol's molecular weight. An essential result is that the OTR of the properly prepared scCO 2 TPS x ET y film was merely 4.3 cm 3 /m 2 ∙day∙atm, which is small enough to meet the demand of high oxygen barrier packaging application. Dynamic molecular relaxations detected for these films disclosed that ET, ST, and LT were compatible with TPS, as their loads were ≤ the optimum value. The distinctly reduced OTR and FVCC for these properly prepared films are partially attributed to the reinforced molecular interactions between sugar alcohol and TPS's hydroxyl groups when they were prepared with scCO 2 ‐assistance, optimal sugar alcohol loading, and/or smaller sugar alcohol's molecular weight. Highlights High oxygen barrier thermoplastic starch/sugar alcohol blown films were prepared. The lowest oxygen transmission rate of the renewable film was 4.3 cm 3 /m 2 ∙day∙atm. This oxygen transmission rate is qualified for high oxygen barrier application. Boosted oxygen barrier property was ascribed to the reduced free volume values.

The objective of this study was to improve the shelf life and nutrition quality of bread by combination of part‐baked frozen technology and white wheat flour replacement with 0, 10, 20 and 30% (w/w) of whole oat flour (WOF). Part‐baked breads were produced at 200C for 7 min followed by freezing at −18C for 1, 7, 14, 21 and 28 days and re‐baking at 230C for 8.5 min. Increasing the level of WOF enhanced water absorption, dough development time and dough softening while reduced dough stability time. Peak viscosity, trough and final viscosities reduced while pasting temperature increased. Baking weight loss increased with frozen storage time but reduced with addition of WOF. Frozen storage time and flour replacement enhanced bread density and firmness. Inclusion of maximum 10% WOF resulted in bread with similar sensory properties to those of control with a minimum shelf life of 28 days at −18C.Practical ApplicationsOat grains are well known for their health benefits and have been used in bread and other foods to improve their nutritional value. Oat bread has been produced already by conventional methods, while there is little information to show the possibility of production of oat bread using part‐baked frozen breads technology. This technology has a growing market as it can enhance the quality and shelf life of the bread. The results of this research indicated that replacement of maximum 10% wheat flour with whole oat flour can result in satisfactory part‐baked bread with frozen shelf life of 28 days. This study can provide further information on application of whole oat flour as an excellent source of dietary fiber (mainly β‐glucan) and bioactive compounds with health benefits in bread production industry in order to respond to the increasing demand for a wider variety of healthy breads with longer shelf life.

Bread dough is usually fermented with yeast but in the present study sourdough lactic acid bacteria (Lactobacillus bulgaricus) alone and in combination with yeast (Saccharomyces cerevisiae) were used to determine their effect on the shelf life and sensory characteristics of bread at different intervals of storage. Lactic acid bacteria improved the sensory characteristics of bread such as volume, evenness of bake, character of crust, grain of bread, colour of bread crumb, aroma, taste and texture of bread and extended shelf life of bread by inhibiting the growth of microbes.

Changes in Microbial Parameters and Gas Composition During Modified Atmosphere Storage of Fresh Pork Loin Cuts

Instant powdered complementary food is a commercial product designed to meet the nutritional needs of infants aged 6-11 months. This study aimed to determine the shelf life of instant powdered complementary food products fortified with moringa flour using semi-aluminum foil packaging based on microbial and mold growth parameters. The product was prepared from a mixture of ingredients such as wheat flour, mocaf flour, soybean flour, chicken eggs, ultra-high temperature milk, and vegetable oil, according to the SNI 01-7111.1-2005 standards. The study used the accelerated shelf-life testing method with the Arrhenius equation model, storing the products at 30°C, 40°C, and 50°C for 28 days. Results showed that total microbial and mold counts increased significantly at 30°C and 40°C over 28 days, while storage at 50°C led to a decline in microbial counts and slower mold growth. Using the Arrhenius-based first-order model, the predicted shelf life increased with temperature, reaching up to 92.7 days based on microbial growth and 40.8 days based on mold growth at 50°C. This trend is attributed to the lower reaction rate constants (k values) at higher temperatures, indicating slower deterioration. However, since mold growth was the limiting factor, the shortest shelf-life estimate, 33.5 days at 30°C, should be considered for practical labeling. It is therefore recommended to store moringa-fortified instant complementary food packaged in semi-aluminum foil at or below 30°C to suppress microbial activity and maintain product safety and quality throughout its shelf life. These results highlight the importance of temperature control in extending the product’s microbial stability and suggest further real-time studies to validate shelf life under typical storage conditions.

ABSTRACT- Considering health and economic issues, today, consumers have become more concerned with foods which contain natural ingredients. Hence, in this study, the effects of plum concentrate and puree which were incorporated into the Taftoon bread formulation at different levels on the rheological, baking properties and shelf life of bread were evaluated. Results showed that addition of plum concentrate and puree improved the quality and shelf life of Taftoon bread. Plum puree was effective in improving dough development time, mixing tolerance index and dough softening while concentrate affected stability and water absorption. Bread containing 4% plums puree had the lowest hardness compared with other samples. Image processing analyses showed that both concentrate and puree improved browning in Taftoon bread. Therefore, plum concentrate and puree can be used as a humectant to improve the quality and shelf life of Taftoon bread.

Thin polymer‐based coatings with high oxygen barrier at elevated humidity are needed for the protection of food and organic electronic devices. Polyelectrolyte‐based thin films (deposited via layer‐by‐layer assembly) perform well at ambient humidity, but their performance typically dwindles as humidity increases due to their hydrophilic nature. Retention of their high barrier can be achieved through the addition of chemical crosslinkers or the introduction of inorganic platelets that create a nanobrick wall structure. In this study, a nanobrick wall barrier prepared with two types of clay, with a thickness less than 200 nm, is shown to reduce the oxygen transmission rate (OTR) of 179 µm polyethylene terephthalate to less than 0.016 cm3 m−2 day−1 atm−1. At 90% relative humidity (RH), a quadlayer barrier consisting of polyethylenimine, boehmite clay, poly(acrylic acid), and vermiculite clay maintains nearly 90% of its barrier performance at 0% RH (OTR = 0.019 cm3 m−2 day−1 atm−1). This study demonstrates the potential of dual clay thin film nanocomposites to protect various consumer goods at high humidity.

Multilayered thin films, with high oxygen barrier, were deposited from water using chitosan (CH), polyacrylic acid (PAA), and montmorillonite (MMT) clay. Layer-by-layer assembly of ten “quadlayers” of CH/PAA/CH/MMT (<100 nm thick) on polylactic acid (PLA) and polyethylene terephthalate (PET) films, commonly used for food packaging, reduced the oxygen transmission rate (OTR) of PLA and PET films by two orders of magnitude under dry conditions. At 38°C and 90% RH, the OTR of 500 μm PLA was reduced from 50 to 4·6 cc/(m2 day atm), which is lower than 179 μm PET film under the same conditions. This high gas barrier is believed to be due a to a nanobrick wall structure present in this thin film, where clay platelets act as bricks held together by polymeric mortar. These assembled thin films are also very transparent, which combined with ambient processing and the use of renewable and food contact approved ingredients, makes this a promising foil replacement technology.