Single-Gelator Structuring of Hemp Oil Using Agarose: Comparative Assembly, Electronic Nose Profiling, and Functional Performance of Hydroleogels Versus Oleogels in Shortbread Cookies

Abstract

This study demonstrates an innovative single-gelator approach using agarose (1% and 2% w/w) to structure cold-pressed hemp oil into functional fat replacers for shortbread cookies, achieving a 40% reduction in saturated fatty acids compared to butter. Comprehensive characterization revealed that hydroleogels exhibited superior crispiness (45.67 ± 3.86 N for 2% agarose hydroleogel-HOG 2%) but problematic water activity (0.39-0.61), approaching microbial growth thresholds. Conversely, oleogels showed lower crispiness (2.27-3.43 N) but optimal moisture control (aw = 0.12-0.16) and superior color stability during 10-day storage. Electronic nose analysis using 10 metal oxide sensors revealed that oleogel systems preserved characteristic aroma profiles significantly better than hydroleogels, with 2% agarose oleogel (OG 2%) showing 34% less aroma decay than pure hemp oil. The 2% agarose oleogel demonstrated optimal performance with minimal baking loss (5.87 ± 0.20%), excellent structural integrity, and stable volatile compound retention over storage. Morphological analysis showed that hemp oil cookies achieved the highest specific volume (2.22 ± 0.07 cm³/g), while structured systems ranged from 1.12 to 1.31 cm³/g. This work establishes agarose as a versatile single gelator for hemp oil structuring and validates electronic nose technology for the objective quality assessment of fat-replaced bakery products, advancing healthier food design through molecular approaches.

Keywords: agarose; electronic nose; fat replacement; hemp oil; hydroleogel; oleogel; shortbread; texture; water activity.

Figure 1

Color differences (∆E) in fat-based cookies and dough samples.

Figure 2

PEN3 sensor response diagram of shortbread cookies with different fat types. W1C (1): aromatics, benzene, toluene; W5S (2): nitrogen oxides, reactive gases; W3C (3): ammonia, amines; W6S (4): hydrogen, H₂S; W5C (5): propane, methane, aliphatic hydrocarbons; W1S (6): methane (CH₄); W1W (7): H₂S, sulfur-containing VOCs; W2S (8): ethanol, CO; W2W (9): aromatics, organic sulfides; W3S (10): long-chain alkanes (e.g., hexane, pentane).