Functionalization of electrospun fish gelatin mats with bioactive agents: Comparative effect on morphology, thermo-mechanical, antioxidant, antimicrobial properties, and bread shelf stability.

In the current study, fish gelatin-based nanofiber mats were embedded with different bioactive agents (BAs) such as cinnamaldehyde (CEO), limonene (LEO), and eugenol (EEO) at 1, 3, and 5% via electrospinning, and their effects on the morphological, structural, mechanical, thermal, antioxidant, antimicrobial, and bread packaging properties of the mats were evaluated. The gelatin mats presented different physicochemical properties due to the inherent differences in the chemical structure of the added BAs and their interaction with the gelatin chains. The conductivity, surface tension, and viscosity of gelatin dopes changed with the presence of the BAs, yet the electrospun nanofibers showed defect-free uniform morphology as confirmed by electron microscopy, with no significant change in the chemical structure of gelatin. The melting temperature of gelatin mats remained in the range of 187-197°C. The mats presented lower tensile strength and elongation at break by the addition of BAs compared with the pristine gelatin mat. The highest radical scavenging (90%) was yielded by mats with EEO, while mats with CEO depicted better antibacterial activity with an inhibition zone of 18.83 mm. However, a dose-dependent increase in the antifungal properties was noticed for all the mats. The mats retained almost 50% of BAs after 60 days of storage at 45% relative humidity. Electrospun gelatin mats inhibited the aerobic bacteria (81%) and yeast and molds (61%) in preservative-free bread after 10 days of storage.

Effects of blanching and pickling process on the alcohol acyltransferase (AAT) activity, myristicin content and quality parameters of pickled nutmeg (Myristica fragrans).

Myristicin, a potential toxicant, is a major ester present in the pericarp of nutmeg (Myristica fragrans) and alcohol acyltransferase (AAT) is responsible for its generation. The objective of the study was firstly to estimate the effect of blanching and pickling process on the inactivation of AAT and production of myristicin in nutmeg pericarp. Secondly, the effect of pickling process on the physical, microbial, antioxidant and sensory properties of nutmeg was evaluated. The nutmeg fruit pericarp was water-blanched for 0, 3, 5, 7 and 9 min. The increased blanching time significantly (p < 0.05) reduced the AAT activity (3.478 U/mg protein) compared to fresh nutmeg (39.034 U/mg protein). The reduction of myristicin was so efficient that it could not be detected after 9 min of blanching. Similarly, the pickling process significantly (p < 0.05) inhibited the AAT activity and lowered the myristicin content. However, the blanching significantly (p < 0.05) lowered the total phenol content and reduced the free radical scavenging capacity of pickled nutmeg (BP) when compared with commercial pickled nutmeg. Blanched pickled nutmeg (BP) presented the same color characteristics as of commercial one, although significant reduction in hardness was observed. No growth of yeast and mold was noticed for all the blanched pickled nutmeg. The sensory analysis data demonstrated that blanching up to 7 min maintained the overall acceptability of pickled nutmeg as of commercial pickled nutmeg. Thus, the study suggests that blanching and pickling treatment improved the quality of nutmeg effectively by inhibiting the AAT activity and reducing the myristicin content.

Effects of osmotic dehydration treatment on volatile compound (Myristicin) content and antioxidants property of nutmeg (Myristica fragrans) pericarp.

The effects of osmotic dehydration (OD) treatment on volatile compound (myristicin) content and the antioxidant capacity of nutmeg (Myristica fragrans) were studied. Fresh nutmeg pericarps were treated with varying sugar concentrations (60, 70, 80%) with different soaking periods at ambient temperature. The OD-treated nutmeg extracts were analyzed for myristicin content via Gas Chromatography Flame Ionization Detector. The phenolic content and antioxidant capacity were analyzed using Follin-Ciocalteu and a free radical scavenging activity assay. The myristicin content was highest (1.69 mg/100 mg) at 80% sugar concentration after 3 h of soaking. Total phenolic content and free radical scavenging activity were highest at 3 h of 80% sugar solution treatment with values of 76.90% and 1.75 mg GAE/g, respectively. OD treatment at varying sugar concentration levels and durations affects the production of myristicin and antioxidant composition. Treatment of nutmeg with OD at 80% sugar concentration for 3 h is preferable, resulting in an acceptable level of myristicin and high antioxidants.

In vitro calcium availability in bakery products fortified with tuna bone powder as a natural calcium source.

Avoidance of dairy products due to lactose intolerance can lead to insufficiency of calcium (Ca) in the body. In an approach to address this problem, tuna bone powder (TBP) was formulated as a calcium supplement to fortify bakery products. In a study, TBP recovered by alkaline treatment contained 38.16 g/100 g of calcium and 23.31 g/100 g of phosphorus. The ratio of Ca:P that was close to 2:1 was hence comparable to that in human bones. The availability of calcium in TBP was 53.93%, which was significantly higher than most calcium salts, tricalcium phosphate (TCP) being the exception. In vitro availability of calcium in TBP-fortified cookies or TCP-fortified cookies were comparable at 38.9% and 39.5%, respectively. These values were higher than the readings from TBP-fortified bread (36.7%) or TCP-fortified bread (37.4%). Sensory evaluation of bakery products containing TBP or TCP elicited comparable scores for the two additives from test panels. Hence, TBP could be used in the production of high calcium bakery products that would enjoy consumer acceptance.

Synthesis of polyhydroxyalkanoate from palm oil and some new applications.

Polyhydroxyalkanoate (PHA) is a potential substitute for some petrochemical-based plastics. This biodegradable plastic is derived from microbial fermentation using various carbon substrates. Since carbon source has been identified as one of the major cost-absorbing factors in PHA production, cheap and renewable substrates are currently being investigated as substitutes for existing sugar-based feedstock. Plant oils have been found to result in high-yield PHA production. Malaysia, being the world's second largest producer of palm oil, is able to ensure continuous supply of palm oil products for sustainable PHA production. The biosynthesis and characterization of various types of PHA using palm oil products have been described in detail in this review. Besides, by-products and waste stream from palm oil industry have also demonstrated promising results as carbon sources for PHA biosynthesis. Some new applications in cosmetic and wastewater treatment show the diversity of PHA usage. With proper management practices and efficient milling processes, it may be possible to supply enough palm oil-based raw materials for human consumption and other biotechnological applications such as production of PHA in a sustainable manner.