Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

การปรับปรุงความสามารถในการอุ้มน้ำและผลผลิตของกุ้งขาวโดยสารทดแทนฟอสเฟตและไบคาร์บอเนต

Thesis (M.Sc. (Food Science and Technology)--Prince of Songkla University, 201

Development of edible films and coatings made from biomaterials to extend the shelf life of fresh fruit

主

Physico-chemical and gel properties of agar from Gracilaria tenuistipitata from the lake of Songkhla, Thailand

Physico-chemical and gelling properties of agar extracted from Gracilaria tenuistipitata as affected by alkaline pretreatments using NaOH and KOH at various levels (3e7%, w/v) were investigated. Yield of native agar was 17.1%, whilst those of agars pretreated with NaOH and KOH ranged from 23.6% to 26.1%. Agar with alkaline pretreatment generally showed the better gelling property as evidenced by higher gel strength, gelling, melting temperatures and viscosity with coincidentally increased 3,6-anhydrogalactose (3,6-AG) content than did native agar. Additionally, native agar had a higher sulphate content with lower syneresis (P < 0.05) than those with alkaline pretreatment. Regardless of alkaline concentration, NaOH used for pretreatment rendered agar with a higher quality, compared with KOH. Agar (1.5%, w/v) pretreated with 5% NaOH exhibited the highest gel strength (482 g/cm2) with high yield (25.3%). The decrease in total sulphate content and the increase in 3,6-AG content were observed in agar having 5% NaOH pretreatment as determined by FTIR spectroscopy. Finer and more compact network with smaller pores was visualised in gel from agar with 5% NaOH pretreatment. Therefore, the appropriate pretreatment by using 5% NaOH could increase yield and improve the gelling property of agar from G. tenuistipitata harvested from the lake of Songkhla, Thailand

Optimization of extraction of phenolic compounds and antioxidants from passion fruit and rambutan seeds using response surface methodology

Passion fruit seed (PS) and rambutan seed (RS) contain sizable amounts of phenolic compounds (PCs) with bioactive compounds including antioxidant activity (AOA). The aim of this study was to optimize the extraction of PCs from PS and RS using response surface methodology (RSM). Preliminary results indicated that the solid to liquid (S-L) ratio of 1:40 (w/v) showed the highest yield (EY) for PS and RS, with values of 11.59 ± 0.08 and 14.55 ± 1.67 g/100 g samples, respectively. The S-L ratio of 1:30 (w/v) was selected as an economic logistic. The predicted response compared to experimental data for EY, EPC, DPPH, ABTS and FRAP of the extracts were 12.41 % (12.68 %), 715 (707), 85 (81), 539 (522) and 107 (160) mg GAE/100 g dry weight for RS and 13.68 % (14.41 %), 3141 (3235), 1327 (1434), 5793 (5564) and 1567 (1509) mg GAE/100 g dry weight for PS, respectively. The experimental data, including EY, EPC, and AOA, were fitted using a 2nd order polynomial equation. The statistical analysis revealed that ethanol concentration and extraction temperature significantly influenced PS (p < 0.001), whereas ethanol concentration primarily affected RS on the EY and EPC. The multiple regression analysis suggested that AOA of PS was significantly affected by linear, quadratic, and interaction of ethanol concentration, extraction time and temperature. Nonetheless, the AOA of RS was only affected by ethanol concentration. The best possible combinations for PS and RS were ethanol concentration 67 and 54 %, extraction temperature 94 and 63 °C, and extraction time 186 and 221 min, respectively, to obtain the maximum EY, extractable phenolic compounds (EPC) and AOA. The composite desirability values for the optimal conditions of PS and RS were 0.74 and 0.68, respectively. Optimal aqueous phenolic extracts from PS and RS could serve as sustainable food-grade ingredients and nutraceutical products

Optimization of microwave-assisted extraction of phenolic compounds and antioxidants from Careya sphaerica Roxb. flowers using response surface methodology

Careya sphaerica Roxb. flowers are good sources of phenolic compounds (PCs) with bioactive properties such as antioxidant activity. The objective of this study was to optimize the extraction parameters for microwave-assisted extraction (MAE) of PCs from C. sphaerica Roxb. flowers, utilizing response surface methodology (RSM) through a central composite design. The extraction of PCs was significantly (p < 0.05) impacted by process variables. The best possible combinations were microwave power (MP) 1000 W, solid to solvent (S-S) ratio 1:100 g: mL, ethanol concentration 40 % v/v, and extraction time 20 s to obtain the maximum extraction yield (EY), extractable phenolic compounds (EPC), DPPH and total flavonoid content (TFC). The maximum EY, EPC, DPPH, and TFC of 70.4 g, 33,504 mg GAE, 24,355 mg GAE and 13,115 mg CE, respectively were obtained per 100 g dry mass. The result suggests that MP and S-S ratio significantly (p < 0.05) affect the extraction of PCs and DPPH. All of the models applied to fit the responses were significant (p < 0.01) and suitable to represent the relationship between independent variables and responses. The study revealed the effectiveness of MAE using RSM for the extraction of PCs from C. sphaerica flowers

Impact of environmental storage conditions on properties and stability of a smart bilayer film

International audienceThis study aimed to investigate the behavior of smart bilayer films under various temperature and relative humidity (RH). Smart bilayer films were fabricated using sodium alginate with incorporated butterfly pea anthocyanin and agar containing catechin–lysozyme. Cellulose nanospheres were added at concentrations of 0% and 10% w/w of the film and subjected to test at 4 °C and 25 °C, considering different RHs (0%, 50%, and 80%). The results showed that RH had a greater impact on the mechanical properties than temperature, leading to a decrease in tensile strength and an increase in elongation at break with higher RH. The films displayed increased strength but reduced flexibility at low temperatures. Oxygen permeability was negatively affected by increasing RH, while water vapor barrier properties were better at 25 °C than at 4 °C. In terms of color stability, the temperature played a more important role, with both types of smart bilayer films retaining their color stability throughout 14-day storage at 4 °C, even maintaining their ability to change color with pH. However, the films stored at 25 °C exhibited lower color stability and showed potential for color change with varying pH levels, but with lower intensity. The findings of this study demonstrate the significant impact of temperature and RH on the functional properties of smart bilayer films, with and without the addition of cellulose nanospheres. Such smart bilayer films have great potential for various applications, particularly in food packaging, where maintaining color, mechanical, and barrier properties under varying environmental conditions is crucial

Effects of UV–C Treatment on Green Mold Rot (Penicillium digitatum) and Physico– Chemical Properties of Post–Harvest Strawberry Using UV–C Conveyer Machine

We investigated the effects of Ultraviolet–C (UV–C) treatment on inactivation of green mold rot (Penicillium digitatum) and physico–chemical properties of strawberry fruit. Although, there was no significant difference (P≥0.05) in weight loss for all samples after immediately UV–C treatment, however, the loss dramatically increased during storage (P<0.05). During storage, inoculated strawberry treated with UV–C (1 and 6 min) showed the better inactivation effect as evidenced by lower decay and number of microorganism than control sample; however, UV–C treatment for 6 min caused quality damage. This result agreed with browning calyx shriveling and drying of the strawberry simultaneously with firmness decreasing. Thus, the low UV–C treatment (1 min) was recommended to use as a postharvest mild treatment

Development of fish snack (Keropok) with sodium reduction using alternative salts (KCl and CaCl2)

The incidence of non-communicable diseases (NCDs) caused by excessive sodium intake is becoming an important issue that many researchers have investigated. Processing is an effective way to add value to underutilized fish species. Thus, the objective of this research was to develop a fish snack (Keropok) using reduced sodium. Two types of alternative sodium chloride (NaCl) were used, namely potassium chloride (KCl) and calcium chloride (CaCl2) with substitution at levels of 15, 30, and 45 % (w/w). The results indicated that substitution of NaCl with KCl or CaCl2 in the product had a negative effect on the cooking yield (%) (P0.05) and the lowest sodium content (P0.05). B3 was rich in nutrients (macromolecules and micromolecules) that are essential to the human body. Therefore, Kerepok (55 % NaCl with 45 % KCl: B3) could be considered as a healthy snack