Days Of Storage Research Articles

Optimising Conditions for the Preservation of Extremely Oxygen Sensitive Obligate Anaerobes of the Gut Microbiota as Candidates for Probiotic Strains

Obligate anaerobic difficult culture bacteria, which make up the bulk of the microbiota of the large intestine, are potential candidates for the development of highly effective new generation probiotics, since they are capable of synthesizing a variety of metabolites, including short-chain fatty acids, which have a stimulating effect on both commensal bacteria and host cells. However, for their long-term preservation, it is necessary to carefully select the preservation method and protective components. To evaluate the efficacy of using different cryoprotectants to increase the viability of obligate anaerobic difficult culture bacteria when preserved by lyophilisation and cryopreservation methods. The studies showed that freeze-drying contributed most to the preservation of the viability of Faecalibacterium prausnitzii, Anaerostipes hadrus, Eubacterium hallii, provided that they were used as a stabilizing medium, which included inulin, cysteine and riboflavin, ensuring the preservation of the initial bacterial titer for 30 days. Among the studied bacteria, the effectiveness of cryopreservation was shown for A. hadrus, since it ensured the survival of bacteria at the initial level for 14 days of storage, regardless of the cryopreservative used, but by the 30th day their viability decreased significantly (by 100 times when using liquid as a cryopreservant). nutrient medium 110 with minced meat and carbohydrates with the addition of glycerin, 10 000 with the commercial cryopreservative CRYOINSTANT). The results obtained allow us to recommend lyophilization as the most optimal method for long-term storage of probiotic strains of bacteria using highly effective stabilizers.

Vechur cow milk yoghurt: response surface methodology-based process optimization and storage studies.

In this research article, response surface methodology (RSM) based optimization of three production parameters namely temperature, time and amount of starter culture of Vechur cow milk yoghurt (VCMY) on the basis of sensory evaluation responses comparing cross-bred cow milk yoghurt (CCMY) as the control is reported. The optimized values of production parameters were 2.15 per cent rate of inoculation, 42°C incubation temperature and 4 h incubation period. The optimized product exhibited significantly lower syneresis, a*, b* values and higher L* values than CCMY. Physico-chemical, microbiological, textural and sensory properties of both VCMY and CCMY during room temperature and refrigerated storage were assessed daily until the onset of spoilage (room temperature) or at five day intervals over a period of 15 d (refrigerated). Both room temperature stored products were graded undesirable by the sensory panel upon one day of storage. Significant reduction was observed in the fat, SNF, total solids, protein and pH content and all the tested colour parameters of the optimized product during refrigerated storage. Total viable counts as well as yeast and mould counts and lactic acid bacteria counts of both VCMY and CCMY progressively increased over the 15 d of storage. Significant reductions were observed in the flavour (P < 0.01), body and texture, colour and appearance and overall acceptability (P < 0.05) scores of both the samples over a period of 15 d. During storage, hardness and adhesiveness values showed an increasing trend whereas the cohesiveness showed a decreasing trend. Storage studies revealed significant differences in the acidity, pH, syneresis, tyrosine value, colour parameters and sensorial attributes of both the yoghurt samples. During the 15 d refrigerated storage period, the VCMY exhibited superior technological attributes to CCMY in terms of lower syneresis %, acidity, microbial population, firmer and less cohesive texture, better flavour, colour and appearance scores. Being the first comprehensive study on the utilization of Vechur cow milk for the preparation of yoghurt, the data generated in the current study would provide a solid base for the exploration of fermentation as a means of value addition of milk of this very rare indigenous cattle breed.

Enhanced performance and long-term stability of 2D photodetectors through hexagonal boron nitride encapsulation

Two-dimensional (2D) semiconductor materials, such as molybdenum disulfide (MoS2), demonstrate considerable potential for optoelectronic applications, largely due to their atomic thickness, tunable bandgap, and capacity for heterostructure integration. Nevertheless, the development of 2D photodetectors that can achieve high responsivity, a fast response time, and long-term stability remains a significant challenge. The present study is a systematic investigation of the effects of top and bottom encapsulation with hexagonal boron nitride (h-BN) on the performance and stability of 2D photodetectors. By employing a dry transfer process to fabricate a high-quality h-BN/MoS2/h-BN structure, we provide effective protection against environmental degradation. The encapsulated devices exhibited a responsivity increase of one to two orders of magnitude under 532 nm laser illumination, in comparison to those without encapsulation. Additionally, the rise and decay times were markedly reduced, by approximately two orders of magnitude, from 0.538 and 3.43 ms to 23.1 and 99.6 μs, respectively. Moreover, the devices demonstrated sustained performance over a 60-day storage period, with response times remaining faster than pre-encapsulation levels. This study highlights the potential of h-BN encapsulation for enhancing both the performance and stability of 2D photodetectors, advancing the development of more reliable optoelectronic devices.

Development of poly(lactic acid) nanocomposite films with kaolin/bentonite blended clay for packaging applications

In this study, Kaolinite clay from the North-East Region (NER) of India was blended with bentonite clay and incorporated into poly(lactic acid) (PLA) at different concentrations of: 1%, 3%, 5%, and 7 weight% (wt%) through the solvent casting method. The resulting films were characterized by using the Fourier transform infrared (FTIR) spectroscopy to investigate the interactions among the various functional groups. The X-ray diffraction (XRD) analysis was performed to determine the composites’ structure and crystallinity, while the thermogravimetric analysis (TGA) was employed to assess the thermal stability of the films. Furthermore, mechanical properties, such as the tensile strength, Young’s modulus, and elongation-at-break (%) were evaluated. The maximum tensile strength of 36.9 MPa was attained for the PLA film blended with 7 wt% of clay. However, the elongation-at-break (%) for this specimen was lower when compared to the neat PLA film. Field emission scanning electron microscopy (FE-SEM) analysis provided insights into the morphology of the poly(lactic acid)–NER kaolinite/bentonite blend clay nanocomposite films, thereby revealing significant aggregation and agglomeration within the specimen containing the 5 wt% of filler. Moreover, the packaging application of the films developed was evaluated to enhance the shelf life of fresh black grapes. The results revealed that the unpackaged grapes experienced spoilage, while those wrapped in the films (PLA-7%) developed and showed no signs of deterioration after the 14 days of storage at room temperature. These findings suggest that the newly developed nanocomposite films could serve as an effective option for fruits packaging applications.

Effect of chitosan coating and organic acid salts on quality and shelf life of black tiger shrimp stored at 0° C

AbstractThis study investigated the extension of the shelf life of black tiger shrimp stored at 0 °C by applying treatments with organic acid salt solutions combined with chitosan preservation coatings. Four shrimp samples were included: the control sample, the sample treated with 2.5% sodium citrate solution, the sample treated with 2% chitosan solution, and the sample treated with 2.5% sodium citrate solution followed by 2% chitosan. Sensory, chemical, and microbiological quality factors were monitored over 17 days of storage using quality indices such as the quality index (QI) from the quality index method, hypoxanthine, trimethylamine nitrogen (TMA‐N), total volatile basic nitrogen (TVB‐N), and total viable count (TVC) to assess the shrimp's freshness. As a result, QI and hypoxanthine levels increased linearly with storage time in all shrimp samples. TMA‐N and TVB‐N values exhibited two‐phase linear changes corresponding to the autolysis and decomposition stages of the shrimp. The shelf life was determined to be 8 days for the control sample, 12 days for the citrate sample, 13 days for the chitosan sample, and 15 days for the citrate/chitosan sample. Linear regression equations between the indices and storage time, as well as between the quality indices for each sample, were identified.

Effect of packaging materials and storage temperature on the shelf stability of Awaze paste.

It is well known that deterioration is a big concern in the food supply chain. The problem is more serious in handling of traditional foods in developing country such as Ethiopia, due to the limited knowledge about the optimum processing, packaging and storage conditions. This study aimed to investigate the effect of packaging material and storage condition on the shelf life of Ethiopian traditional Awaze paste. Six types of packaging materials were employed: Shekella pot, Gourd (Qelle), high-density polyethylene (plastic bag), plastic bottle, glass bottle and metal can. These packaging materials are traditionally used by household producers and cottage industries in Ethiopia. The paste was stored at two temperatures: room temperature (21 ± 2°C) and refrigeration temperature (4°C). Physical changes, color (a) value, pH, acidity, yeast and mold levels, total bacterial count (TBC), and lactic acid bacteria count (LAB) were assessed every 60 days over a period of 300 days. pH value, acidity, yeast and mold, TBC, and LAB count were significantly (p < 0.05) affected by packaging material, storage temperature and storage period. After 300 days of storage, the highest yeast and mold count, 4.06 log CFU/g, was observed in samples stored in plastic bags. The highest total bacterial count (TBC), 4.12 log CFU/g, was found in samples stored in metal cans. The samples stored in glass bottles at refrigeration temperature (4°C) were found to have a color (a*) value difference of 11.5 to 13.85, a yeast and mold count value of 3.2 log cfu/g, and a TBC value of 2.97 log cfu/g, which were acceptable after 300 days of storage as per the international food standards. Taking into account all parameters including physical changes (color, mold growth, texture), acidity, yeast and mold, TBC, and LAB count, Awaze paste could be stored in glass bottles at 4°C for up to 300 days.

The Probiotication of a Lychee Beverage with Saccharomyces boulardii: An Alternative to Dairy-Based Probiotic Products.

Probiotic vegetable-based beverages, such as lychee, can be rich in nutrients, free of cholesterol and lactose, and also have few allergenic components. Saccharomyces boulardii is an alternative to make lychee juice a probiotic beverage. This work aimed to develop probiotic lychee beverage (LB) using S. boulardii by evaluating the effect of refrigerated storage on cell viability, physicochemical characteristics, and acceptance. LB supplemented with S. boulardii was fermented (24 h/30 °C), supplemented with sucrose (4-12 °Brix), and refrigerated (up to 28 days/4 °C). The yeast viability, total soluble solid (TSS) and, ethanol content, pH, total phenolic compounds (TPC), and antioxidant activity (AA) levels were evaluated over 28 days of storage. Also, the profiles of sugars, organic acids, and phenolic were determined via chromatographic analysis. The sensory acceptance of the probiotic beverage was evaluated. Higher sucrose levels (12 °Brix) resulted in greater yeast viability (6.9 log CFU/mL) on the 21st day of storage and superior TPC (153 µmol TEAC/mL) and ethanol levels (8.7%). Storage reduced the TPC, AA, and TSS. LB supplemented with sucrose to 12 °Brix, probioticated by S. boulardii, and stored for 21 days became accepted by the consumer and presented an adequate physicochemical profile with probiotic potential. The probiotication of lychee beverage is an alternative to dairy-based probiotic beverages.

High pressure and heat-induced potato protein nanocomplexes as carriers for curcumin: influence of pH and curcumin addition pathway

Abstract This study aimed to assess the potential of high hydrostatic pressure (HHP) and heat treatment (HT) in facilitating the formation of nanoassemblies of potato proteins (PPs) and curcumin to protect this sensitive bioactive compound. Curcumin was introduced into patatin-rich protein dispersions (4% wt/wt) according to two pathways: before (pathway 1) or after (pathway 2) HHP treatment (400 or 600 MPa for 8 hr at pH 6 and pH 7) or HT (55 °C for 5 min at pH 6) to optimize curcumin–protein complexation efficiency (CE). Treatments increased PP surface hydrophobicity which facilitated curcumin binding and protein aggregation, as confirmed by protein particle size increase. The highest CE was obtained with pathway 1 at 600 MPa pH 7, while HT limited curcumin complexation. Whatever the pathway, the antioxidant activity of the processed dispersions treated at 600 MPa for 8 hr or 55 °C for 5 min was increased compared to untreated ones and preserved after 10 days of storage at 4 °C. These nanocomplexes could potentially be applied in functional foods.

The effect of Coriandrum sativum L. on yogurt: a comprehensive study of physicochemical, microbiological, sensory, and textural properties.

The objective of this study was to investigate the effects of the addition of Coriandrum sativum L. (coriander) on the physicochemical, sensory, textural and microbiological properties of yogurt. To conduct this study, 4 types of yogurt were prepared as control (C0) and with 1% (C1), 2% (C2) and 3% (C3) coriander, and the yogurts were analyzed on specific storage days. The addition of coriander significantly influenced some physiochemical parameters (syneresis, titratable acidity) of yogurts (p < 0.05). The storage time significantly affected the water holding capacity (WHC), syneresis and titratable acidity (TA). The TA of the yogurts increased during storage. The addition of coriander significantly influenced the color parameters (ΔE, C* and YI) of yogurts (p < 0.05). The results of the statistical analysis indicated that storage time had a significant effect on the viability of yogurt bacteria (p < 0.05). While the number of Lactobacillus bulgaricus decreased, an increase was observed in the number of Streptococcus thermophilus. The number of both yogurt bacteria remained above 7.46 log cfu/g throughout storage. The addition of coriander to yogurt led to changes in the number of yogurt bacteria. When the texture parameters of the yogurts were compared, no significant difference was seen between the yogurts. The sensory evaluation showed that yogurts with coriander had a higher overall acceptability than C0 yogurts. The results of the research indicate that the addition of coriander has a positive effect on the quality of yogurt. The results of this study suggest that the inclusion of coriander and other similar aromatic plants in yogurt production could be beneficial in terms of producing functional yogurt and the potential uses of these plants should be investigated.

Nebulized Hybrid Nanoarchaeosomes: Anti-Inflammatory Activity, Anti-Microbial Activity and Cytotoxicity on A549 Cells.

The properties of two hybrid nanoarchaeosomes (hybrid nanoARCs) made of archaeolipids extracted from the halophilic archaea Halorubrum tebenquichense and combining the properties of archaeolipid bilayers with metallic nanoparticles are explored here. BS-nanoARC, consisting of a nanoARC loaded with yerba mate (Ilex paraguariensis) extract (YME)-biogenic silver nanoparticles (BSs), and [BS + BS-nanoARC], consistent of a BS-nanoARC core covered by an outer shell of BSs, were structurally characterized and their therapeutic activities screened. By employing 109 ± 5 µg gallic acid equivalents (GAEs) and 73.4 µg chlorogenic acid/ YME mg as a silver reductive agent, spherical, heterogeneously sized (~80 nm diameter), -27 mV ζ potential, 90% Ag0 and λmax 420 nm BSs were obtained. We further prepared ~100-200 nm diameter, -57 mV ζ potential BS-nanoARC and ~300 nm diameter, -37 mV ζ potential [BS + BS-nanoARCs]. Freshly prepared and nebulized BS-nanoARCs reduced the release of TNF-α, IL-6 and IL-8 by LPS-irritated THP-1-macrophages and were highly anti-planktonic against S. aureus (MIC90: 13 ± 0.8 µg Ag/mL). While the nanoARCs and BS-nanoARCs were innocuous, freshly prepared [BS + BS-nanoARCs] magnified the cytotoxicity of BSs (IC50 12 µg Ag/mL vs. IC50 ~36 µg Ag/mL) on A549 cells. Such cytotoxicity remained after 30 days in the dark at 4 °C, while that of BSs was lost. Freshly prepared BSs also lost activity upon nebulization, whereas freshly prepared [BS + BS-nanoARCs] did not. However, the cytotoxicity of the [BS + BS-nanoARCs] was also lost when nebulized after 30 days of storage. Despite the harmful effects of storage and mechanical stress on the structure of the more active [BS + BS-nanoARCs], hybrid nanoARCs are promising examples of nanomedicines combining the properties of archaeolipids with antimicrobial silver nanoparticles and anti-inflammatory polyphenols that could complement oncologic therapies, reducing the usage of classical antitumoral agents, corticosteroids, and, importantly, of antibiotics, as well as their waste.

Construction of Pickering Double Emulsions Based on Xanthan Gum/Lysozyme Nanoparticles: Structure, Stability, and Co-Encapsulation of Epigallocatechin Gallate and β-Carotene.

The low stability of water-in-oil-in-water (W1/O/W2) double emulsions greatly limits their applications. Therefore, in this study, W1/O/W2 Pickering double emulsions (PDEs) were prepared by a two-step emulsification method using polyglycerol polyricinoleate (PGPR) and xanthan gum/lysozyme nanoparticles (XG/Ly NPs) as lipophilic and hydrophilic emulsifiers, respectively. The regulation mechanism of the performance of PDEs by XG/Ly NPs was investigated, and the ability of the system to co-encapsulate epigallocatechin gallate (EGCG) and β-carotene was evaluated. The results showed that increasing the XG/Ly NPs concentration can enhance the stability of PDEs. At 60% W2 phase percentage and 2.0% XG/Ly NPs, the PDEs showed a smaller droplet size (23.47 ± 2.28 μm) and no phase separation after 21 days of storage. Additionally, the PDEs co-encapsulated system showed higher encapsulation efficiency (EGCG: 89.21%; β-carotene: 99.14%) and maintained high retention of active substances after 8 h of UV illumination (EGCG: 75.51%; β-carotene: 77.24%). As demonstrated by in vitro simulated gastrointestinal digestion assays, the bioaccessibility of EGCG and β-carotene simultaneously encapsulated was improved by 66.0% and 36.2%, respectively, compared with that of individually encapsulated EGCG and β-carotene. Overall, this study provides a new reference for the construction of highly stable PDEs and is promising as a co-encapsulation carrier for environmentally sensitive components.

Fruit quality retention and shelf-life extension of papaya through organic coating.

Papaya (Carica papaya L.) is a climacteric fruit which lose quality and shelf life quickly due to physiological decay and microbial infection after harvest. The study was conducted to evaluate newly applied clybio formulation (0.2%) along with the existing effective concentration of chitosan (1%), aloevera gel (50%), seaweed extract (1%) and uncoated papaya (control) fruits on post-harvest physicochemical properties and disease incidence when stored at 25±1°C and 85-90% relative humidity. Quality parameters were available up to 12 days of storage (DAS) for chitosan and clybio treated papaya where it was 9 DAS for aloevera gel and seaweed treated papaya and 6 DAS for control papaya. Before decay of all the coated papaya at 9 DAS, chitosan (1%) performed superior in retaining maximum reducing sugar (0.77%, 1.41% and 3.85% more than aloevera, seaweed and clybio application, respectively), β-carotene (10.94%, 12.5% and 9.89% greater than aloevera, seaweed and clybio coatings, respectively), total flavonoids content (18.36%, 29.81% and 25.29% better than aloevera, seaweed and clybio treatments, respectively), total antioxidant activity (21.85%, 68.2% and 47.91% than noted in aloevera, seaweed and clybio formulations, respectively) and potassium content (3.14% and 9.32% than aloevera and clybio treatments, respectively). In addition, clybio gave better results over chitosan up to completion of shelf life (12 DAS) such as retention of ascorbic acid (6.21%), non-reducing sugar (13.48%), magnesium content (8.31%) and disease incidence (20%). Thus, besides preserving nutraceutical property, chitosan and clybio coated papaya remained edible for further 6 days compared to control, and 3 days over aloevera gel and seaweed extract treatment. These findings suggest the use of chitosan and clybio formulation for preserving quality parameters and extending the storage life of papaya.

A Simple and Effective Method for the Cryopreservation of Quillwort Spores

ABSTRACTQuillworts are highly threatened worldwide and many Isoëtes species have been suffering population decreases. Isoëtes cangae is a lycophyte endemic from a single Amazon lake that has been challenging due to climate change and deforestation of the Amazon rainforest. The development of strategies for ex situ conservation of lycophyte germplasm is urgent to prevent biodiversity losses. Spores of I. cangae were obtained from specimens collected in situ. Samples were submitted to three different moisture conditions: hydrated, air‐dry desiccation and drying in silica gel. Desiccated samples were stored in an ultrafreezer (−80°C) or liquid nitrogen (−196°C) and the hydrated spores at room temperature. The spore viability was evaluated through spore germination (G) and sporeling emergence (SE) indices after 30, 90, 180 and 275 days of storage. The growth of emerged sporophytes was evaluated after 3 months. Desiccated–cryopreserved spores had high G% and SE%, even after 275 days of storage, and did not differ from hydrated spores. Hydrated spores had higher daily emergence and a longer time to maximum sporophyte emergence than desiccated spores, but not in all storage periods. Sporophytes that emerged from hydrated and desiccated spores had a similar development. Both desiccated methods and temperatures of storage maintained spore viability high. The methodologies tested in this study are novel for the genus and represent a significant step towards the ex situ conservation of quillworts.

Cold Storage Effects on Quality Attributes and Bioactive Compounds of Moroccan Pomegranate Varieties

Pomegranate is a seasonal fruit known for its high nutritional quality but with a limited shelf life. Thus, cold storage is frequently utilized as a conservation technique to prolong the shelf life of pomegranate fruits. Nevertheless, the valuable nutritional properties and technological quality of pomegranates can degrade notably over storage time. The aim of this study is to evaluate the chemical and technological stability of five pomegranate cultivars (“Purple Queen,” “Smith,” “Mr100,” “Sefri Ouled Abdellah,” and “Kingdom”) during cold storage. These cultivars represent the most widely cultivated varieties in the region and are among the most significant and predominant in Morocco, but they have a limited postharvest shelf life. The study evaluated various aspects including technological quality (weight loss, color attributes (L∗, a∗, b∗, C∗, and h°)), physicochemical parameters (pH, total soluble solids (TSSs), and titratable acidity (TA)), and bioactive compounds (total phenolic content (TPC), total anthocyanin content (TAC), condensed tannins (CTs), and total flavonoid content (TFC)) over 120 days of cold storage at 4°C. The findings indicated that the weight loss and pH increased gradually for all cultivars, with “Mr100” showing a significant increase in weight loss (0%–29.12%) and pH (4.01 to 4.76). Regarding TPC, TFC, and TAC, all cultivars exhibited substantial reductions in bioactive compounds over storage period, with the “Kingdom” variety experiencing high TAC losses, averaging 84.82%, while “Sefri Ouled Abdellah” showed notable TPC losses, averaging 69.97%. In addition, “Mr100” and “Smith” showed high CTs and TFC losses. Briefly, cold storage significantly impacts the chemical composition and overall quality of pomegranate fruits. This study offers new insights into the storage stability, conservation aptitude, and potential shelf‐life enhancement of these specific cultivars over 120 days of cold storage at 4°C. These findings can be valuable for producers and the food industry, as they highlight the importance of monitoring storage conditions to optimize pomegranate quality and extend shelf life, ultimately improving consumer satisfaction and reducing waste.

Influence of selenium additives on butter quality and storage stability

The study's results showed that using Selenium preparations in butter production inhibited oxidative processes occurring during butter storage. In such a product, the oxidative changes of the butter were slowed down, resulting in the product's quality parameters being preserved longer. Before storage, the butter was evaluated in the 45 to 43 points range. After 15 days of storage, the taste and odour scores of the oil ranged from 44 to 40 points. The highest score was assigned to samples with high fat content stored at minus 5°C. The 62.5 per cent fat samples stored at 15°C had the lowest score for this storage period. When stored for more than 30 days, there was a further decrease in the taste and odour score of the oil. It scored between 41 and 37 points during this storage period. In addition, only sweet butter stored at minus temperature remained in the high grade. At the last storage stage (60 days), the butter scored from 38 to 35 points. Summarising the presented data, it should be noted that using selenium in butter production inhibits the development of oxidative processes and slows the deterioration of organoleptic characteristics during product storage. The rate of these processes depends on the storage temperature and the amount of oil in the butter. Due to the use of Selenium at the temperature of Minus 5 °C the shelf life of butter of the highest grade increases by 1.6-2.0 times, at 5 °C, by 1.8-2.4 times and at 15 °C, by 2.4-3.0 times. The non-infinite fatty acids in the milk fat of the cows we study are less than infinite acids, as indicated by the value of glyceride solid fractions and the amount of iodine. The iodine index in cows of the Alatau breed was 28.62, while for those in the third lactation and beyond, it was 28.45. The iodine index values for Holstein cows were 28.86 and 28.7, respectively.

Impact of high-intensity ultrasound on interfacial protein adsorption of non-dairy whipping cream: Whipping properties and foam stabilization model

In this paper, the competitive adsorption and practical application characteristics of ultrasound treatment on the oil-water interface in non-dairy whipping cream were explored. The results showed that ultrasound treatment promoted the competitive adsorption of casein, resulting in an increase of interfacial protein loading in the system by 4.82 mg/m2 and a decrease in oil droplet size by 0.20 μm. In addition, due to the increase of interfacial protein in the system, the partial coalescence of the fat globule of systems decreased, which led to a rapid collapse of the foam after 2 days of storage. Ultrasound weakened the strength of the gel network inside emulsions, which weakened the anti-deformation ability of emulsions. Although the LVR of the ultrasonically treated samples narrowed after churning, the G′ value increased. In addition, the stress yield point of the foams shifted to higher strains as the ultrasonic power increased, implying better resistance to deformation.

Coating based on Montmorillonite, essential oils, and amaranth to preserve mango

Abstract This study aimed to evaluate the coating based on Amaranthus flour (AF), montmorillonite, and three essential oils (clove, muña, and matico) to extend the shelf life of minimally processed mango. The mango cubes were divided into four different treatments. T1- control (uncoated mango), T2 (0.3% w/v of clove), T3 (0.3% w/v of muña), and T4 (0.3% w/v of matico). All treatments had 0.6% w/v Amaranth flour and 0.02% w/v montmorillonite (MMT) and were subjected to 5°C for 12 days. Water activity (Aw), pH, Total soluble solids, acidity, weight loss, color, texture, and antimicrobial activity were evaluated for each treatment. Matico treatment maintained pH and had the lowest count of yeast and mold forming units on mango (3.47 log UFC g-1). On the last day of storage, all coating treatments showed less weight loss and favorable results than the control. The matico treatment showed higher efficiency for mango preservation.

In-situ aqueous phase encapsulation immobilized lipase assisted by acidic ionic liquids for the synthesis of isoamyl acetate

In this study, two acidic ionic liquids were innovatively selected to replace traditional acetic acid as catalysts and templates for the preparation of covalent organic frameworks (COFs) materials in aqueous phase at room temperature. At the same time, the synthesized COFs carrier achieved in-situ encapsulation and immobilization of Candida rugosa lipase (CRL) in aqueous phase at room temperature. The optimum immobilized lipases COF-COOH-M and COF-SO3H-M were obtained by adjusting the reaction conditions. Their enzyme loadings were 210.17 mg/g and 258.47 mg/g, respectively, and the specific activity retention compared to free lipase was 67.11% and 78.42%, respectively. The carrier and immobilized lipase were characterized by FT-IR, XRD, BET and TG. The catalytic performance and operational stability of the immobilized lipase were investigated. The results showed that both immobilized lipases showed better stability than free lipases, and COF-SO3H-M had the best performance. The relative activity retention of COF-SO3H-M after incubation at 60 °C for 60 minutes was 4.35 times that of free lipase. After 28 days of storage at 4 °C, the relative activity of COF-SO3H-M remained 75.10%, while that of free lipase was only 24.61%. The COF-SO3H-M was applied as biocatalyst for isoamyl acetate preparation at 50 °C for 7 hours, and the yield of isoamyl acetate was as high as 86.94%, which was 22.12% higher than that of free lipase.

Immobilization of lipase on mesoporous silica nanocarriers for efficient preparation of phytosterol esters

Phytosterol esters (PEs) are favored for their good solubility, high bioavailability, and various health benefits. Mesoporous silica (MS) nanocarriers were synthesized and utilized to immobilize free lipase AYS “Amano” (from Candida rugosa) for further preparing PEs. The optimal immobilization conditions were an initial enzyme content of 160 mg/mL, pH of 7.0, temperature of 30 °C, and adsorption time of 6 h, resulting in a protein loading of 42.3 mg/g and an immobilization efficiency of 73.4 %. Compared to commercial carriers, MS carriers demonstrated superior immobilization efficiency and phytosterol conversion rates when soybean oil was used as the PEs source for the transesterification. The phytosterol conversion rate reached 97.7 % in a solvent system with optimal reaction conditions. After 30 days of storage, the immobilized lipase retained 55.7 % of its activity, and it had 63.0 % retention activity after 10 reuse cycles. This study significantly enhanced the lipase's phytosterols conversion and reusability, supporting sustainable and efficient industrial production of PEs.

A comparative study of starch granule-associated proteins/lipids on short-term and long-term retrogradation of normal and waxy corn starches.

To evaluate the contribution of starch granule-associated proteins/lipids (SGAPs/SGALs) to the short- and long-term retrogradation of starch, a comparative study was conducted using normal and waxy corn starches. Following the removal of SGAPs, peak viscosity (3504.71 cP) and breakdown viscosity (1659.20 cP) significantly increased, while pasting temperature (74.31 °C) significantly decreased, compared to SGALs-removed (3131.00 cP, 1229.80 cP, 75.46 °C) and native normal corn starches (2704.40 cP, 794.60 cP, 79.30 °C). Rheological profiles further revealed that the removal of SGAPs/SGALs effectively promoted the short-term retrogradation of amylose, as evidenced by larger hysteresis rings and higher consistency indices (K) in the SGAPs/SGALs-removed starch gel. While SGAPs removal also greatly facilitated amylopectin recrystallization and double helix structure aggregation than removal of SGALs, thereby significantly increased the retrogradation enthalpy (from 6.48 to 7.37 J g-1) and gel hardness (from 461.26 gf to 518.31 gf) in normal corn starch after 14 days of storage, while no notable differences were observed in their corresponding waxy counterparts after both treatments. In conclusion, SGAPs showed significant superiority over SGALs in accelerating both short- and long-term retrogradation of normal corn starch, while both had minimal impact on waxy corn starch.