Vacuum extraction: an effective larval sampling method for spotted-wing drosophila in small fruit crops

Detecting and sampling the pest for pest management, either through enumerating their life stages or by quantifying the crop damage, is the cornerstone in deploying integrated pest management. Currently, for spotted-wing drosophila, Drosophila suzukii Matsumura, larval extraction from the fruit samples involves immersing the fruits in hot water, salt, or sugar solution. We are introducing a novel, fast, and effective larval sampling technique where D. suzukii larvae can be extracted from infested fruits by subjecting the fruit samples to vacuum pressure. We optimized the vacuum pressure and vacuum duration for larval extraction from blueberries by testing a range of vacuum pressures and durations. A vacuum pressure of -98 kPa for 60 min resulted in the maximum larval recovery of the small, medium, and large larvae from blueberries. A 30-min incubation at -98 kPa also yielded similar results. Larval extraction at -98 kPa for 60 min on average recovered 61, 70, and 83% of larvae from 2, 4, and 6-day incubated fruit samples, respectively. The fruit sample size (37, 149, and 298 g) did not affect the larval extraction efficacy. Additionally, comparing larval extraction efficacy at -98 kPa with the salt and sugar extraction, incubated for 10, 30, and 60 min, suggests that vacuum extraction is comparable to or more efficient than the salt and sugar methods in extracting larvae from the infested blueberries. Overall, our results indicate that vacuum sampling is a promising method for detecting D. suzukii larval infestation in small fruit crops.

Structure-Function Guided Extraction and Scale-Up of Pea Protein Isolate Production

The lack of adequate guidance and control of the extraction conditions as well as the gap between bench- and industrial-scale production, contributes to the poor functionality of commercial pea protein isolate (cPPI). Therefore, pea protein extraction conditions were evaluated and scaled up to maximize protein purity and yield, while maintaining structural integrity, following mild alkaline solubilization with isoelectric precipitation and salt solubilization coupled with membrane filtration. Both extraction methods resulted in high protein yield (>64%) and purity (>87%). Structure-function characterization illustrated the preserved structural integrity of PPI samples and their superior solubility, gelation, and emulsification properties compared to cPPI. Results confirmed, for the first time, that double solubilization at mild pH (7.5) can replace single solubilization at high alkalinity and achieve a similar yield while preserving structural integrity. Additionally, this study demonstrated, the scalability of the benchtop salt extraction coupled with ultrafiltration/diafiltration. Scaling up the production eliminated some structural and functional differences between the salt-extracted PPI and pH-extracted PPI. Scaling-up under mild and controlled conditions resulted in partial denaturation and a low degree of polymerization, coupled with the superior functionality of the produced isolates compared to cPPI. Results of this work can be used as a benchmark to guide the industrial production of functional pea protein ingredients.

Effect of solvent composition on the extraction of proteins from hemp oil processing stream

BACKGROUND

Hempseed meal, a by-product of the hempseed oil processing stream, is a potential alternative source for food proteins. Efficient extraction of proteins from hempseed meal is challenging owing to differences in the structure and solubility of various protein fractions present in the seed. In the present study, protein was extracted from hempseed meal using four different solvents, including aqueous NaOH, KOH, NaHCO₃ and NaCl, at four different concentrations with the aim of improving the recovery of protein fractions rich in essential amino acids.

RESULTS

Extraction using alkaline solvents provided superior protein recovery (60-78%) compared with NaCl solution and control extractions (20-48% and 21%, respectively). The concentration of alkali or salt (0.25-1 mol L^-1 ) had a minor but significant impact on the yield. Amino acid composition analysis revealed that hempseed meal contains 24% (54.5 ± 0.19 mg g^-1 ) essential amino acids of total amino acids, and extraction with NaOH, KOH, NaHCO₃ or NaCl did not improve the selective extraction of essential amino acids compared to control experiments. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis allowed the identification of edestin and albumin in the extracts obtained with NaHCO₃ and NaCl solvents, with results further showing that the type of extraction solvent influences protein extraction selectivity.

CONCLUSION

Although alkali solvents provide superior extraction yields, extraction with water resulted in extracts containing the highest proportion of proteins bearing essential amino acids. According to the results of SDS-PAGE, extraction using alkali solvents induced protein crosslinking. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Nuclear triiodothyronine-binding protein: partial characterization and binding to chromatin

Nuclei were prepared by sucrose sedimentation of liver homogenates from rats given (125)I-labeled triiodothyronine in vivo. The nuclear extract obtained by treatment of the nuclear pellet with 0.4 M KCl contains the [(125)I]triiodothyronine that had been injected in vivo bound to protein(s). The triiodothyronine bound to nuclear protein(s) in vivo does not readily exchange with triiodothyronine added to the extract in vitro. This triiodothyronine.nuclear extract complex retains triiodothyronine during dialysis or exposure to anion exchange resin and migrates as a broad band on agarose-gel electrophoresis. It is rapidly destroyed by Pronase, by 8 M urea, and by p-chloromercuribenzoic acid, but not by RNase or by DNase. It is also susceptible to thermal inactivation at 37 degrees , possibly through changes in the affinity of triiodothyronine to the nuclear binding protein(s), since the bound triiodothyronine becomes more readily dialyzable, is absorbed by an anion exchange resin, but retains its characteristic mobility on electrophoresis. The triiodothyronine.nuclear extract complex formed in vivo binds to crude liver chromatin in vitro at low salt concentration, but can be completely extracted again at KCl concentrations greater than 0.2 M.